bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Investigation on the Role of Mechanical Factors Contributing to Globe Flattening in States of Elevated Intracranial Pressure
Authors: Mehr Jafar A. , Moss Heather E. , Hatami-Marbini Hamed
Published: November 2020

Flattening of the posterior eye globe in the magnetic resonance (MR) images is a sign associated with elevated intracranial pressure (ICP), often seen in people with idiopathic intracranial hypertension (IIH). The exact underlying mechanisms of globe flattening (GF) are not fully known but mechanical factors are believed to play a role. In the present study, we investigated the effects of material properties and pressure loads on GF. For this purpose, we used a generic finite element model to investigate the deformation of the posterior eyeball. The degree of GF in numerical models and the significance of different mechanical factors on GF were characterized using an automated angle-slope technique and a statistical measure. From the numerical models, we found that ICP had the most important role in GF. We also showed that the angle-slope graphs pertaining to MR images from five people with high ICP can be represented numerically by manipulating the parameters of the finite element model. This numerical study suggests that GF observed in IIH patients can be accounted for by the forces caused by elevation of ICP from its normal level, while material properties of ocular tissues, such as sclera (SC), peripapillary sclera (PSC), and optic nerve (ON), would impact its severity.
Automatic Electronic Invoice Classification Using Machine Learning Models
Authors: Bardelli Chiara , Rondinelli Alessandro , Vecchio Ruggero , Figini Silvia
Published: November 2020

Electronic invoicing has been mandatory for Italian companies since January 2019. All the invoices are structured in a predefined xml template which facilitates the extraction of the information. The main aim of this paper is to exploit the information contained in electronic invoices to build an intelligent system which can simplify accountants’ work. More precisely, this contribution shows how it is possible to automate part of the accounting process: all the invoices of a company are classified into specific codes which represent the economic nature of the financial transactions. To accomplish this classification task, a multiclass classification algorithm is proposed to predict two different target variables, the account and the VAT codes, which are part of the general ledger entry. To apply this model to real datasets, a multi-step procedure is proposed: first, a matching algorithm is used for the reconstruction of the training set, then input data are elaborated and prepared for the training phase, and finally a classification algorithm is trained. Different classification algorithms are compared in terms of prediction accuracy, including ensemble models and neural networks. The models under comparison show optimal results in the prediction of the target variables, meaning that machine learning classifiers succeed in translating the complex rules of the accounting process into an automated model. A final study suggests that best performances can be achieved considering the hierarchical structure of the account codes, splitting the classification task into smaller sub-problems.
Two-Tailed Fuzzy Hypothesis Testing for Unilateral Specification Process Quality Index
Authors: Yu Chun-Min , Luo Win-Jet , Hsu Ting-Hsin , Lai Kuei-Kuei
Published: November 2020

The quality characteristics with unilateral specifications include the smaller-the-better (STB) and larger-the-better (LTB) quality characteristics. Roundness, verticality, and concentricity are categorized into the STB quality characteristics, while the wire pull and the ball shear of gold wire bonding are categorized into the LTB quality characteristics. In terms of the tolerance, zero and infinity (∞) can be viewed as the target values in line with the STB and LTB quality characteristics, respectively. However, cost and timeliness considerations, or the restrictions of practical technical capabilities in the industry, mean that the process mean is generally far more than 1.5 standard deviations away from the target value. Researchers have accordingly proposed a process quality index conforming to the STB quality characteristics. In this study, we come up with a process quality index conforming to the LTB quality characteristics. We refer to these two types of indices as the unilateral specification process quality indices. These indices and the process yield have a one-to-one mathematical relationship. Besides, the process quality levels can be completely reflected as well. These indices possess unknown parameters. Therefore, sample data are required for calculation. Nevertheless, interval estimates can lower the misjudgment risk resulting from sampling errors more than point estimates can. In addition, considering cost and timeliness in the industry, samples are generally small, which lowers estimation accuracy. In an attempt to increase the accuracy of estimation as well as overcome the uncertainty of measured data, we first derive the confidence interval for unilateral specification process quality indices, and then propose a fuzzy membership function on the basis of the confidence interval to establish the two-tailed fuzzy testing rules for a single indicator. Lastly, we determine whether the process quality has improved.
Robust Control Design to the Furuta System under Time Delay Measurement Feedback and Exogenous-Based Perturbation
Authors: Pujol-Vazquez Gisela , Mobayen Saleh , Acho Leonardo
Published: November 2020

When dealing with real control experimentation, the designer has to take into account several uncertainties, such as: time variation of the system parameters, exogenous perturbation and the presence of time delay in the feedback line. In the later case, this time delay behaviour may be random, or chaotic. Hence, the control block has to be robust. In this work, a robust delay-dependent controller based on H∞ theory is presented by employing the linear matrix inequalities techniques to design an efficient output feedback control. This approach is carefully tuned to face with random time-varying measurement feedback and applied to the Furuta pendulum subject to an exogenous ground perturbation. Therefore, a recent experimental platform is described. Here, the ground perturbation is realised using an Hexapod robotic system. According to experimental data, the proposed control approach is robust and the control objective is completely satisfied.
AIRC: Attentive Implicit Relation Recommendation Incorporating Content Information for Bipartite Graphs
Authors: Ma Xintao , Dong Liyan , Wang Yuequn , Li Yongli , Sun Minghui
Published: November 2020

With users being exposed to the growing volume of online information, the recommendation system aiming at mining the important or interesting information is becoming a modern research topic. One approach of recommendation is to integrate the graph neural network with deep learning algorithms. However, some of them are not tailored for bipartite graphs, which is a unique type of heterogeneous graph having two entity types. Others, though customized, neglect the importance of implicit relation and content information. In this paper, we propose the attentive implicit relation recommendation incorporating content information (AIRC) framework that is designed for bipartite graphs based on the GC–MC algorithm. First, through reconstructing the bipartite graphs, we obtain the implicit relation graphs. Then we analyze the content information of users and items with a CNN process, so that each user and item has its feature-tailored embeddings. Besides, we expand the GC–MC algorithms by adding a graph attention mechanism layer, which handles the implicit relation graph by highlighting important features and neighbors. Therefore, our framework takes into consideration both the implicit relation and content information. Finally, we test our framework on Movielens dataset and the results show that our framework performs better than other state-of-art recommendation algorithms.
Effects of Ultralow-Tidal-Volume Ventilation under Veno-Venous Extracorporeal Membrane Oxygenation in a Porcine Model with Ventilator-Induced Lung Injury
Authors: Lim Sung Yoon , Cho Young-Jae , Kim Dong Jung , Kim Jun Sung , Jheon Sanghoon , Chung Jin Haeng , Lee Jae Ho
Published: November 2020

Low-tidal-volume ventilation decreases mortality in acute respiratory distress syndrome (ARDS) patients. This study investigated the effects of ultralow tidal ventilation under veno-venous extracorporeal membrane oxygenator (ECMO) support in pigs with ARDS. Eight pigs were intubated and inoculated with methicillin-resistant Staphylococcus aureus through bronchoscopy. Ultralow tidal ventilation (3 mL/kg) under extracorporeal membrane oxygenator (ECMO) support was applied to one group and high tidal ventilation (15 mL/kg) was applied to another group to maintain comparable oxygenation for 12 h without ECMO support. Each group had similar arterial blood gas values and hemodynamic variables at baseline and during the experiment. The high-tidal-volume ventilation group showed a gradual decline in arterial oxygen levels, and repeated ANOVA showed significant differences in oxygenation change over time in the ultralow tidal ventilation group. Inflammatory cytokine levels in the bronchoalveolar lavage fluid and lung ultrasound scores were similar between two groups. Histologic analysis showed that both groups developed pneumonia after 12 h; however, the ultralow tidal ventilation group had a lower lung injury score assessed by the pathologist. We developed the first ultralow-tidal-volume ventilation porcine model under veno-venous ECMO support. The ultralow-tidal-volume ventilation strategy can mitigate mechanical ventilator-associated lung injury.
Removal of Enantiomeric Ibuprofen in a Nanofiltration Membrane Process
Authors: Higgins Carlyn J. , Duranceau Steven J.
Published: November 2020

A study of the behavior of R- and S-enantiomers of ibuprofen (R-IBU and S-IBU) in aqueous solution by nanofiltration (NF) membranes revealed that up to 23% of the pharmaceutical was adsorbed onto the stainless steel equipment of a flat-sheet experimental unit. Mass balances disclosed that IBU’s S-enantiomer was primarily responsible for the adsorption onto the equipment. Additional IBU adsorption was also experienced on the NF membrane coupons, verified by increased contact angle measurements on the surfaces. The IBU-equipment adsorptive relationship with and without the membrane coupon were best described by Freundlich and Langmuir isotherms, respectively. At a feed water pH of 4.0 units and racemic µg/L IBU concentrations, NF removal ranged from 34.5% to 49.5%. The rejection of S-IBU was consistently greater than the R-enantiomer. Adsorption onto the surfaces influenced NF rejection by 18.9% to 27.3%. The removal of IBU displayed a direct relationship with an increase in feed water pH. Conversely, the adsorption of IBU exhibited an indirect relationship with an increase in feed water pH.
New Polymer Inclusion Membrane in the Separation of Nonferrous Metal Ion from Aqueous Solutions
Authors: Pyszka Ilona , Radzyminska-Lenarcik Elzbieta
Published: November 2020

The new polymer inclusion membrane (PIM) with ethylenediamine-bis-acetylacetone (EDAB-acac) matrix was used for the separation of Zn(II) solutions containing non-ferrous metal ions (Co(II), Ni(II) Cu(II), Cd(II)). The effective conditions for carrying out transport studies by PIMs were determined on the basis of solvent extraction studies. The values of the stability constants and partition coefficients of M(II)-EDAB-acac complexes were determined from the extraction studies. The stability constants increase in series Ni(II) < Cu(II) < Co(II) < Cd(II) < Zn(II), and their logarithms are 8.85, 10.61, 12.73, 14.50, and 16.84, respectively. The transport selectivity of the PIMs were: Zn(II) > Cd(II) > Co(II) > Cu(II) > Ni(II). The established stability constants of the complexes also decrease in this order. The values of three parameters: initial flux, selectivity coefficient, and recovery factor of a given metal after 12 h were selected for the comparative analysis of the transport process. The highest values of the initial fluxes were received for Zn(II), Cd(II), and Co(II). They are, depending on the composition of the mixture, in the range 9.87–10.53 µmol/m2, 5.26–5.61 µmol/m2, and 7.43–7.84 µmol/m2 for Zn(II), Co(II), and Cd(II), respectively. The highest recovery factors were observed for Zn(II) ions (90–98.0%). For Cd, Co and Cu, the recovery factors are high and are within the range 76–83%, 64–79%, and 51–66%, respectively.
Experimental Analysis and Behaviour Modelling of the Deformation Mechanisms of a Ti-6242S Alloy under Hot and Superplastic Forming Conditions
Authors: Song Longqiu , Ii Anzu , Despax Laurie , Onishi Hatsumi , Matsumoto Hiroaki , Velay Vincent , Vidal Vanessa
Published: November 2020

In this work, the hot deformation characteristics of a near-α Ti-Al-2SnZr-2Mo alloy (Ti6242 alloy) with a Fine-Grained (FG) microstructure (dα = 2.86 μm) were investigated at two levels of temperature, T = 730 ∘C and T = 840 ∘C. The initial microstructure consists of equiaxed nodules of the α phase as well as some α lamellae sparsely distributed and separated by thin layers of the BCC β phase. For both temperatures, three strain rates (10−4,10−3,10−2s−1) were analysed during loading. Moreover, the microstructural evolution (α size and morphology) was also evaluated by conducting interrupted tensile tests. The different tensile testing conditions greatly influence the stress-strain response of the material as well as the microstructure evolution. Indeed, various phenomena can take place such as elongation of the grain structure, globularization, dynamic recrystallization and grain growth of the equiaxed areas depending on the temperature, the strain rate and the strain level. The FG Ti6242 alloy exhibits interesting superplastic ductility at T = 840 ∘C. At this temperature either a very gradual flow softening (at higher strain rate) or flow hardening (at lower strain rate) can be observed and are related respectively to one or more of the following mechanisms: lamellae globularization, DRX and grain growth. At the intermediate strain rate, both mechanisms, strain hardening and softening, coexist. At T = 730 ∘C, the onset of the α lamellae globularization was only promoted at low strain rate. A mechanical behavior model was developed in the temperature range of 730–840 ∘C, which was able to take into account all the observed phenomena: viscosity, softened behavior and strain hardening. Constitutive equations were calibrated from the stress-strain responses and microstructural observations, and the computed results were in good agreement with the experiments.
Cyclic Behavior of Hollow Section Beam–Column Moment Connection: Experimental and Numerical Study
Authors: Nuñez Eduardo , Boainy Nwar , González Freddy , Torres Ronald , Picón Ricardo , Guerrero Néstor
Published: November 2020

Steel buildings with tubular columns showed a satisfactory performance during the Honshu (2011) earthquake, unlike steel buildings in the 1994 Northridge and 1995 Kobe earthquakes, where welded moment connections showed damage in their joints. In this research, a lateral joint using a hollow structural section (HSS)-beam and HSS-column subjected to cyclic displacement was performed. Three large-scale specimens were tested and a numerical model was calibrated, reaching a good adjustment. Later, several configurations of beams and columns were evaluated using finite element (FE) models from the numerical model previously calibrated. A flexural resistance higher 0.80 Mp at 0.04 [rad] was obtained for all cases studied. The ductility factor in the 3 specimens was lower than 2.5, therefore a non-ductile behavior was controlled in the connection. This aspect is very important although a 0.8 Mp at 0.04 [rad] was achieved. Finally, the typical welded moment connection can be improved using the bolted moment connection, which allows the concentration of inelastic incursion in the beam compared with the welded solution. However, a non-ductile behavior derived from local buckling in flanges of a tubular beam can affect the seismic performance.
Quantum Dots: An Emerging Tool for Point-of-Care Testing
Authors: Singh Suchita , Dhawan Aksha , Karhana Sonali , Bhat Madhusudan , Dinda Amit Kumar
Published: November 2020

Quantum dots (QDs) are semiconductor crystals in the nanodimension having unique optical and electronic properties that differ from bulk material due to quantum mechanics. The QDs have a narrow emission peak, size-dependent emission wavelength, and broad excitation range which can be utilized for diverse biomedical applications such as molecular imaging, biosensing, and diagnostic systems. This article reviews the current developments of biomedical applications of QDs with special reference to point-of-care testing.
Development of Proportional–Integrative–Derivative (PID) Optimized for the MicroElectric Discharge Machine Fabrication of Nano-Bismuth Colloid
Authors: Tseng Kuo-Hsiung , Chang Chaur-Yang , Cahyadi Yagus , Chung Meng-Yun , Hsieh Chin-Liang
Published: November 2020

Metal nanoparticles are typically prepared by using a chemical method, and a suspension is added to control the particle size and concentration of the nanoparticles. In this study, a micro-electric discharge machine (micro-EDM) was used to melt bismuth into nanoparticles, thus yielding a colloidal solution. No chemicals were added during the manufacturing process, and pure water was used as the medium. The colloid was assessed using an electrohydraulic system, and process parameters were adjusted for optimization; additionally, the discharge pulse wave was analyzed. The proposed preparation process is simple, fast, and cost-effective; moreover, the manufacturing process allows for mass production and reduces environmental pollution. Experimental results revealed that the nano-bismuth (nano-bi) colloidal solution was successfully prepared by the micro-EDM, and absorption peaks in the UV-vis spectrum were observed at 234 and 237 nm. Moreover, to optimize the proportional–integral–derivative (PID) control parameters to be used in the micro-EDM to prepare the nano-bi colloidal solution, this study derived a mathematical model of the micro-EDM. MATLAB was used to obtain the PID parameters. The discharge success rate (74.1876%) for the nano-bi colloidal solution prepared using our method was higher than that (46.9196%) obtained for a nano-bi colloidal solution prepared using an online adaptation method.
Characterization of a Murine Model for Encephalitozoon hellem Infection after Dexamethasone Immunosuppression
Authors: An Guozhen , Tang Yunlin , Mo Biying , Ran Maoshuang , He Xiao , Bao Jialing , Zhou Zeyang
Published: November 2020

Background: Encephalitozoon hellem (E. hellem) belongs to a group of opportunistic pathogens called microsporidia. Microsporidia infection symptoms vary and include diarrhea, ocular disorders and systemic inflammations. Traditionally, immunodeficient animals were used to study microsporidia infection. To overcome the difficulties in maintenance and operation using immunodeficient mice, and to better mimic natural occurring microsporidia infection, this study aims to develop a pharmacologically immunosuppressed murine model of E. hellem infection. Methods: Wild-type C57BL/6 mice were immunosuppressed with dexamethasone (Dex) and then E. hellem spores were inoculated into the mice intraperitoneally. Control groups were the Dex-immunosuppressed but noninoculated mice, and the Dex-immunosuppressed then lipopolysaccharide (LPS)-treated mice. Mice body weights were monitored and all animals were sacrificed at the 15th day after inoculation. Tissue fragments and immune cells were collected and processed. Results: Histopathological analysis demonstrated that E. hellem inoculation resulted in a disseminated nonlethal infection. Interestingly, E. hellem infection desensitized the innate immunity of the host, as shown by cytokine expressions and dendritic cell maturation. We also found that E. hellem infection greatly altered the composition of host gut microbiota. Conclusions: Dex-immunosuppressed mice provide a useful tool for study microsporidiosis and the interactions between microsporidia and host immunity.
Functional Properties and Sustainability Improvement of Sourdough Bread by Lactic Acid Bacteria
Authors: Fraberger Vera , Ammer Claudia , Domig Konrad J.
Published: November 2020

Preventing food spoilage without the addition of chemical food additives, while increasing functional properties of wheat-based bakery products, is an increasing demand by the consumers and a challenge for the food industry. Within this study, lactic acid bacteria (LAB) isolated from sourdough were screened in vitro for the ability to utilize the typical wheat carbohydrates, for their antimicrobial and functional properties. The dual culture overlay assay revealed varying levels of inhibition against the examined fungi, with Lactiplantibacillus plantarum S4.2 and Lentilactobacillusparabuchneri S2.9 exhibiting the highest suppression against the indicator strains Fusarium graminearum MUCL43764, Aspergillus fumigatus, A. flavus MUCL11945, A. brasiliensis DSM1988, and Penicillium roqueforti DSM1079. Furthermore, the antifungal activity was shown to be attributed mainly to the activity of acids produced by LAB. The antibacillus activity was evaluated by the spot-on-the-lawn method revealing a high inhibition potential of the majority of LAB isolated from sourdough against Bacillus cereus DSM31, B. licheniformis DSM13, B. subtilis LMG7135, and B. subtilis S15.20. Furthermore, evaluating the presence of the glutamate decarboxylase gen in LAB isolates by means of PCR showed a strain dependency of a potential GABA production. Finally, due to improved functional activities, LAB isolated from sourdoughs exhibit promising characteristics for the application as natural preservatives in wheat-based bakery products.
Use of Permanent Wall-Deficient Cells as a System for the Discovery of New-to-Nature Metabolites
Authors: Shitut Shraddha , Bergman Güniz Özer , Kros Alexander , Rozen Daniel E. , Claessen Dennis
Published: November 2020

Filamentous actinobacteria are widely used as microbial cell factories to produce valuable secondary metabolites, including the vast majority of clinically relevant antimicrobial compounds. Secondary metabolites are typically encoded by large biosynthetic gene clusters, which allow for a modular approach to generating diverse compounds through recombination. Protoplast fusion is a popular method for whole genome recombination that uses fusion of cells that are transiently wall-deficient. This process has been applied for both inter- and intraspecies recombination. An important limiting step in obtaining diverse recombinants from fused protoplasts is regeneration of the cell wall, because this forces the chromosomes from different parental lines to segregate, thereby preventing further recombination. Recently, several labs have gained insight into wall-deficient bacteria that have the ability to proliferate without their cell wall, known as L-forms. Unlike protoplasts, L-forms can stably maintain multiple chromosomes over many division cycles. Fusion of such L-forms would potentially allow cells to express genes from both parental genomes while also extending the time for recombination, both of which can contribute to an increased chemical diversity. Here, we present a perspective on how L-form fusion has the potential to become a platform for novel compound discovery and may thus help to overcome the antibiotic discovery void.
The Utilization of Linear Polylysine Coupled with Mechanic Forces to Extract Microbial DNA from Different Matrices
Authors: François Celia , Martinez Celia , Faye Clement , Pansu Nathalie , Dunyach-Remy Catherine , Garrelly Laurent , Roig Benoit , Cadiere Axelle
Published: November 2020

Molecular approaches are powerful tools that are used for medical or environmental diagnoses. However, the main limitations of such a tools are that they extract low levels of DNA and they do not remove the inhibitors of polymerase chain reaction (PCR). Although the use of polycation to complex and purify DNA has been described in the literature, elution often requires a high ionic strength or pH levels not compatible with molecular analyses. In this paper, we described a new process that is based on the complexation of DNA with linear polylysine, followed by capturing the complex by a cation exchange resin. The originality of the process consisted of using mechanic force to elute DNA from the complex. The extraction method showed several advantages when compared to existing methods, such as being compatible with pH levels that range from 5 to 11, as well as high levels of DNA recovery and elimination of PCR inhibitors from complex samples. This method was successfully applied to different types of samples, such as environmental samples, beverage samples, and medical samples. Furthermore, it was proven to be a good solution for removing PCR inhibitors and assuring good DNA recovery yield.
Saccharomyces paradoxus Transcriptional Alterations in Cells of Distinct Phenotype and Viral dsRNA Content
Authors: Ravoitytė Bazilė , Lukša Juliana , Yurchenko Vyacheslav , Serva Saulius , Servienė Elena
Published: November 2020

Killer yeasts are attractive antifungal agents with great potential applications in the food industry. Natural Saccharomyces paradoxus isolates provide new dsRNA-based killer systems available for investigation. The presence of viral dsRNA may alter transcriptional profile of S. paradoxus. To test this possibility, a high-throughput RNA sequencing was employed to compare the transcriptomes of S. paradoxus AML 15-66 K66 killer strains after curing them of either M-66 alone or both M-66 and L-A-66 dsRNA viruses. The S. paradoxus cells cured of viral dsRNA(s) showed respiration deficient or altered sporulation patterns. We have identified numerous changes in the transcription profile of genes including those linked to ribosomes and amino acid biosynthesis, as well as mitochondrial function. Our work advance studies of transcriptional adaptations of Saccharomyces spp. induced by changes in phenotype and set of dsRNA viruses, reported for the first time.
Expansion of Tick-Borne Rickettsioses in the World
Authors: Piotrowski Mariusz , Rymaszewska Anna
Published: November 2020

Tick-borne rickettsioses are caused by obligate intracellular bacteria belonging to the spotted fever group of the genus Rickettsia. These infections are among the oldest known diseases transmitted by vectors. In the last three decades there has been a rapid increase in the recognition of this disease complex. This unusual expansion of information was mainly caused by the development of molecular diagnostic techniques that have facilitated the identification of new and previously recognized rickettsiae. A lot of currently known bacteria of the genus Rickettsia have been considered nonpathogenic for years, and moreover, many new species have been identified with unknown pathogenicity. The genus Rickettsia is distributed all over the world. Many Rickettsia species are present on several continents. The geographical distribution of rickettsiae is related to their vectors. New cases of rickettsioses and new locations, where the presence of these bacteria is recognized, are still being identified. The variety and rapid evolution of the distribution and density of ticks and diseases which they transmit shows us the scale of the problem. This review article presents a comparison of the current understanding of the geographic distribution of pathogenic Rickettsia species to that of the beginning of the century.
Neuroprotective Effects of Quercetin in Pediatric Neurological Diseases
Authors: Alvarez-Arellano Lourdes , Salazar-García Marcela , Corona Juan Carlos
Published: November 2020

Oxidative stress is a crucial event underlying several pediatric neurological diseases, such as the central nervous system (CNS) tumors, autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD). Neuroprotective therapy with natural compounds used as antioxidants has the potential to delay, ameliorate or prevent several pediatric neurological diseases. The present review provides an overview of the most recent research outcomes following quercetin treatment for CNS tumors, ASD and ADHD as well as describes the potential in vitro and in vivo ameliorative effect on oxidative stress of bioactive natural compounds, which seems like a promising future therapy for these diseases. The neuroprotective effects of quercetin against oxidative stress can also be applied in the management of several neurodegenerative disorders with effects such as anti-cancer, anti-inflammatory, anti-viral, anti-obesity and anti-microbial. Therefore, quercetin appears to be a suitable adjuvant for therapy against pediatric neurological diseases.
Effect of CO2 Preservation Treatments on the Sensory Quality of Pomegranate Juice
Authors: Mosca Ana Carolina , Menghi Leonardo , Aprea Eugenio , Mazzucotelli Maria , Benedito Jose , Zambon Alessandro , Spilimbergo Sara , Gasperi Flavia
Published: November 2020

Due to the interest in identifying cost-effective techniques that can guarantee the microbiological, nutritional, and sensorial aspects of food products, this study investigates the effect of CO2 preservation treatment on the sensory quality of pomegranate juice at t0 and after a conservation period of four weeks at 4 °C (t28). The same initial batch of freshly squeezed non-treated (NT) juice was subjected to non-thermal preservation treatments with supercritical carbon dioxide (CO2), and with a combination of supercritical carbon dioxide and ultrasound (CO2-US). As control samples, two other juices were produced from the same NT batch: A juice stabilized with high pressure treatment (HPP) and a juice pasteurized at high temperature (HT), which represent an already established non-thermal preservation technique and the conventional thermal treatment. Projective mapping and check-all-that-apply methodologies were performed to determine the sensory qualitative differences between the juices. The volatile profile of the juices was characterized by gas chromatography-mass spectrometry. The results showed that juices treated with supercritical CO2 could be differentiated from NT, mainly by the perceived odor and volatile compound concentration, with a depletion of alcohols, esters, ketones, and terpenes and an increase in aldehydes. For example, in relation to the NT juice, limonene decreased by 95% and 90%, 1-hexanol decreased by 9% and 17%, and camphene decreased by 94% and 85% in the CO2 and CO2-US treated juices, respectively. Regarding perceived flavor, the CO2-treated juice was not clearly differentiated from NT. Changes in the volatile profile induced by storage at 4 °C led to perceivable differences in the odor quality of all juices, especially the juice treated with CO2-US, which underwent a significant depletion of all major volatile compounds during storage. The results suggest that the supercritical CO2 process conditions need to be optimized to minimize impacts on sensory quality and the volatile profile.
Current Synthetic Routes to Peptidyl Mono-Fluoromethyl Ketones (FMKs) and Their Applications
Authors: Lloyd Carissa M. , Colgin Neil , Cobb Steven L.
Published: November 2020

Peptidyl mono-fluoromethyl ketones (FMKs) are a class of biologically active molecules that show potential as both protease inhibitors for the treatment of a range of diseases and as chemical probes for the interrogation of cellular processes. This review describes the current solid- and solution-phase routes employed for the synthesis of peptidyl mono-FMKs. In addition, it provides a brief overview of some of the key applications of FMKs in the fields of chemical biology and medicinal chemistry.
Bioactive Properties and Phenolic Compound Profiles of Turnip-Rooted, Plain-Leafed and Curly-Leafed Parsley Cultivars
Authors: Liberal Ângela , Fernandes Ângela , Polyzos Nikolaos , Petropoulos Spyridon A. , Dias Maria Inês , Pinela José , Petrović Jovana , Soković Marina , Ferreira Isabel C.F.R. , Barros Lillian
Published: November 2020

Petroselinum crispum Mill., Fuss., is a culinary vegetable used as an aromatic herb that garnishes and flavours a great variety of dishes. In the present study, the chemical profiles and bioactivities of leaf samples from 25 cultivars (three types: plain- and curly-leafed and turnip-rooted) from this species were assessed. Seven phenolic compounds were identified in all the varieties, including apigenin and kaempherol derivates. Apigenin-O-pentoside-O-hexoside was the major compound in all the tested parsley types (20, 22 and 13 mg/g of extract, respectively) and responsible for its excellent antioxidant activity, also investigated in this study. Antimicrobial activities were also explored, and the results revealed a good bioactivity against specific tested pathogens, such as bacteria and fungi. In conclusion, the leaves of all the types of P. crispum are a good source of natural bioactive compounds that confer health benefits, and thus, they should be part of a balanced and diversified diet.
Production of Verbascoside, Isoverbascoside and Phenolic Acids in Callus, Suspension, and Bioreactor Cultures of Verbena officinalis and Biological Properties of Biomass Extracts
Authors: Kubica Paweł , Szopa Agnieszka , Kokotkiewicz Adam , Miceli Natalizia , Taviano Maria Fernanda , Maugeri Alessandro , Cirmi Santa , Synowiec Alicja , Gniewosz Małgorzata , Elansary Hosam O. , Mahmoud Eman A. , El-Ansary Diaa O. , Nasif Omaima , Luczkiewicz Maria , Ekiert Halina
Published: November 2020

Callus, suspension and bioreactor cultures of Verbena officinalis were established, and optimized for biomass growth and production of phenylpropanoid glycosides, phenolic acids, flavonoids and iridoids. All types of cultures were maintained on/in the Murashige and Skoog (MS) media with 1 mg/L BAP and 1 mg/L NAA. The inoculum sizes were optimized in callus and suspension cultures. Moreover, the growth of the culture in two different types of bioreactors—a balloon bioreactor (BB) and a stirred-tank bioreactor (STB) was tested. In methanolic extracts from biomass of all types of in vitro cultures the presence of the same metabolites—verbascoside, isoverbascoside, and six phenolic acids: protocatechuic, chlorogenic, vanillic, caffeic, ferulic and rosmarinic acids was confirmed and quantified by the HPLC-DAD method. In the extracts from lyophilized culture media, no metabolites were found. The main metabolites in biomass extracts were verbascoside and isoverbascoside. Their maximum amounts in g/100 g DW (dry weight) in the tested types of cultures were as follow: 7.25 and 0.61 (callus), 7.06 and 0.48 (suspension), 7.69 and 0.31 (BB), 9.18 and 0.34 (STB). The amounts of phenolic acids were many times lower, max. total content reached of 26.90, 50.72, 19.88, and 36.78 mg/100 g DW, respectively. The highest content of verbascoside and also a high content of isoverbascoside obtained in STB (stirred-tank bioreactor) were 5.3 and 7.8 times higher than in extracts from overground parts of the parent plant. In the extracts from parent plant two iridoids—verbenalin and hastatoside, were also abundant. All investigated biomass extracts and the extracts from parent plant showed the antiproliferative, antioxidant and antibacterial activities. The strongest activities were documented for the cultures maintained in STB. We propose extracts from in vitro cultured biomass of vervain, especially from STB, as a rich source of bioactive metabolites with antiproliferative, antioxidant and antibacterial properties.
Plant Xyloglucan Xyloglucosyl Transferases and the Cell Wall Structure: Subtle but Significant
Authors: Stratilová Barbora , Kozmon Stanislav , Stratilová Eva , Hrmova Maria
Published: November 2020

Plant xyloglucan xyloglucosyl transferases or xyloglucan endo-transglycosylases (XET; EC 2.4.1.207) catalogued in the glycoside hydrolase family 16 constitute cell wall-modifying enzymes that play a fundamental role in the cell wall expansion and re-modelling. Over the past thirty years, it has been established that XET enzymes catalyse homo-transglycosylation reactions with xyloglucan (XG)-derived substrates and hetero-transglycosylation reactions with neutral and charged donor and acceptor substrates other than XG-derived. This broad specificity in XET isoforms is credited to a high degree of structural and catalytic plasticity that has evolved ubiquitously in algal, moss, fern, basic Angiosperm, monocot, and eudicot enzymes. These XET isoforms constitute gene families that are differentially expressed in tissues in time- and space-dependent manners during plant growth and development, and in response to biotic and abiotic stresses. Here, we discuss the current state of knowledge of broad specific plant XET enzymes and how their inherently carbohydrate-based transglycosylation reactions tightly link with structural diversity that underlies the complexity of plant cell walls and their mechanics. Based on this knowledge, we conclude that multi- or poly-specific XET enzymes are widespread in plants to allow for modifications of the cell wall structure in muro, a feature that implements the multifaceted roles in plant cells.
Nanostructured Gels for Energy and Environmental Applications
Authors: Cringoli Maria Cristina , Marchesan Silvia , Melchionna Michele , Fornasiero Paolo
Published: November 2020

Nanostructured gels have emerged as an attractive functional material to innovate the field of energy, with applications ranging from extraction and purification to nanocatalysts with unprecedented performance. In this review we discuss the various classes of nanostructured gels and the most recent advancements in the field with a perspective on future directions of this challenging area.
Role of Graphene in Constructing Multilayer Plasmonic SERS Substrate with Graphene/AgNPs as Chemical Mechanism—Electromagnetic Mechanism Unit
Authors: Liu Lu , Hou Shuting , Zhao Xiaofei , Liu Chundong , Li Zhen , Li Chonghui , Xu Shicai , Wang Guilin , Yu Jing , Zhang Chao , Man Baoyuan
Published: November 2020

Graphene–metal substrates have received widespread attention due to their superior surface-enhanced Raman scattering (SERS) performance. The strong coupling between graphene and metal particles can greatly improve the SERS performance and thus broaden the application fields. The way in which to make full use of the synergistic effect of the hybrid is still a key issue to improve SERS activity and stability. Here, we used graphene as a chemical mechanism (CM) layer and Ag nanoparticles (AgNPs) as an electromagnetic mechanism (EM) layer, forming a CM–EM unit and constructing a multi-layer hybrid structure as a SERS substrate. The improved SERS performance of the multilayer nanostructure was investigated experimentally and in theory. We demonstrated that the Raman enhancement effect increased as the number of CM–EM units increased, remaining nearly unchanged when the CM–EM unit was more than four. The limit of detection was down to 10−14 M for rhodamine 6G (R6G) and 10−12 M for crystal violet (CV), which confirmed the ultrahigh sensitivity of the multilayer SERS substrate. Furthermore, we investigated the reproducibility and thermal stability of the proposed multilayer SERS substrate. On the basis of these promising results, the development of new materials and novel methods for high performance sensing and biosensing applications will be promoted.
Molecular Dynamics Simulations of Ion Drift in Nanochannel Water Flow
Authors: Sofos Filippos , Karakasidis Theodoros , Sarris Ioannis E.
Published: November 2020

The present paper employs Molecular Dynamics (MD) simulations to reveal nanoscale ion separation from water/ion flows under an external electric field in Poiseuille-like nanochannels. Ions are drifted to the sidewalls due to the effect of wall-normal applied electric fields while flowing inside the channel. Fresh water is obtained from the channel centerline, while ions are rejected near the walls, similar to the Capacitive DeIonization (CDI) principles. Parameters affecting the separation process, i.e., simulation duration, percentage of the removal, volumetric flow rate, and the length of the nanochannel incorporated, are affected by the electric field magnitude, ion correlations, and channel height. For the range of channels investigated here, an ion removal percentage near 100% is achieved in most cases in less than 20 ns for an electric field magnitude of E = 2.0 V/Å. In the nutshell, the ion drift is found satisfactory in the proposed nanoscale method, and it is exploited in a practical, small-scale system. Theoretical investigation from this work can be projected for systems at larger scales to perform fundamental yet elusive studies on water/ion separation issues at the nanoscale and, one step further, for designing real devices as well. The advantages over existing methods refer to the ease of implementation, low cost, and energy consumption, without the need to confront membrane fouling problems and complex electrode material fabrication employed in CDI.
Hybrid Transition Metal Dichalcogenide/Graphene Microspheres for Hydrogen Evolution Reaction
Authors: Lunardon Marco , Ran JiaJia , Mosconi Dario , Marega Carla , Wang Zhanhua , Xia Hesheng , Agnoli Stefano , Granozzi Gaetano
Published: November 2020

A peculiar 3D graphene-based architecture, i.e., partial reduced-Graphene Oxide Aerogel Microspheres (prGOAM), having a dandelion-like morphology with divergent microchannels to implement innovative electrocatalysts for the hydrogen evolution reaction (HER) is investigated in this paper. prGOAM was used as a scaffold to incorporate exfoliated transition metals dichalcogenide (TMDC) nanosheets, and the final hybrid materials have been tested for HER and photo-enhanced HER. The aim was to create a hybrid material where electronic contacts among the two pristine materials are established in a 3D architecture, which might increase the final HER activity while maintaining accessible the TMDC catalytic sites. The adopted bottom-up approach, based on combining electrospraying with freeze-casting techniques, successfully provides a route to prepare TMDC/prGOAM hybrid systems where the dandelion-like morphology is retained. Interestingly, the microspherical morphology is also maintained in the tested electrode and after the electrocatalytic experiments, as demonstrated by scanning electron microscopy images. Comparing the HER activity of the TMDC/prGOAM hybrid systems with that of TMDC/partially reduced-Graphene Oxide (prGO) and TMDC/Vulcan was evidenced in the role of the divergent microchannels present in the 3D architecture. HER photoelectron catalytic (PEC) tests have been carried out and demonstrated an interesting increase in HER performance.
Sulfate-Containing Composite Based on Ni-Rich Layered Oxide LiNi0.8Mn0.1Co0.1O2 as High-Performance Cathode Material for Li-ion Batteries
Authors: Savina Aleksandra , Orlova Elena , Morozov Anatolii , Luchkin Sergey , Abakumov Artem
Published: November 2020

Composite positive electrode materials (1−x) LiNi0.8Mn0.1Co0.1O2∙xLi2SO4 (x = 0.002–0.005) for Li-ion batteries have been synthesized via conventional hydroxide or carbonate coprecipitation routes with subsequent high-temperature lithiation in either air or oxygen atmosphere. A comparative study of the materials prepared from transition metal sulfates (i.e., containing sulfur) and acetates (i.e., sulfur-free) with powder X-ray diffraction, electron diffraction, high angle annular dark field transmission electron microscopy, energy-dispersive X-ray spectroscopy, and electron energy loss spectroscopy revealed that the sulfur-containing species occur as amorphous Li2SO4 at the grain boundaries and intergranular contacts of the primary NMC811 crystallites. This results in a noticeable enhancement of rate capability and capacity retention over prolonged charge/discharge cycling compared to their sulfur-free analogs. The improvement is attributed to suppressing the high voltage phase transition and the associated accumulation of anti-site disorder upon cycling and improving the secondary agglomerates’ mechanical integrity by increasing interfacial fracture toughness through linking primary NMC811 particles with soft Li2SO4 binder, as demonstrated with nanoindentation experiments. As the synthesis of the (1−x) LiNi0.8Mn0.1Co0.1O2∙xLi2SO4 composites do not require additional operational steps to introduce sulfur, these electrode materials might demonstrate high potential for commercialization.
Ultra-Stable Polycrystalline CsPbBr3 Perovskite–Polymer Composite Thin Disk for Light-Emitting Applications
Authors: Qaid Saif M. H. , Ghaithan Hamid M. , Al-Asbahi Bandar Ali , Aldwayyan Abdullah S.
Published: November 2020

Organic–inorganic halide organometal perovskites have demonstrated very promising performance in optoelectronic applications, but their relatively poor chemical and colloidal stability hampers the further improvement of devices based on these materials. Perovskite material engineering is crucial for achieving high photoluminescence quantum yields (PLQYs) and long stability. Herein, these goals are attained by incorporating bulk-structure CsPbBr3, which prevents colloidal degradation, into polymethyl methacrylate (PMMA) polymer in thin-disk form. This technology can potentially realize future disk lasers with no optical and structural contributions from the polymer. The polycrystalline CsPbBr3 perovskite particles were simply obtained by using a mechanical processing technique. The CsPbBr3 was then incorporated into the PMMA polymer using a solution blending method. The polymer enhanced the PLQYs by removing the surface trap states and increasing the water resistance and stability under ambient conditions. In our experimental investigation, the CsPbBr3/PMMA composites were extraordinarily stable and remained strongly luminescent after water immersion for three months and air exposure for over one year, maintaining 80% of their initial photoluminescence intensity. The CsPbBr3/PMMA thin disk produced amplified spontaneous emission for a long time in air and for more than two weeks in water.
Waffle-Like Carbons Combined with Enriched Mesopores and Highly Heteroatom-Doped Derived from Sandwiched MOF/LDH/MOF for High-Rate Supercapacitor
Authors: Wu Szu-Chen , Chang Po-Hsueh , Chou Syun-Hong , Huang Chih-Yang , Liu Ta-Chung , Peng Cheng-Hsiung
Published: November 2020

Supercapacitors (SCs) are promising for powering mobile devices, electric vehicles and smart power grids due to their fast charge/discharge rate, high power capability and robust cycle stability. Nitrogen-doped porous carbons are great alternatives because they provide pseudocapacitance without losing their power rate. Nanoporous carbon derived from metal organic frameworks (MOFs) is an ideal precursor for preparing heteroatom-doped carbons due to their abundant nitrogen contents and incredible specific surface areas. However, severe aggregations and the leakage of nitrogen can occur during harsh carbonization. In this study, we used CoAl-LDH (cobalt aluminum layered double hydroxide) as an in-situ growth substrate, allowing Co-based MOF to uniformly grow onto the CoAl-LDH to form a sandwiched MOF/LDH/MOF structure. After acid etching, we obtained waffle-like nanoporous carbons (WNPC). WNPC exhibited high nitrogen and oxygen retention (7.5 wt% and 9.1 wt%) and a broad mesopores distribution with specific surface areas of 594 m2g−1, which promoted a sieving effect. This renders a specific capacitance of 300.7 F·g−1 at 1 A·g−1 and the high retention (72%) of capacitance at 20 A·g−1, ensuring its use at high-rate supercapacitor electrodes. Finally, the WNPC symmetric supercapacitor reaches a superior specific energy of 27 W·h·kg−1 at a power of 500 W·kg−1, and a good cycle stability (85% capacitance retention after 10,000 cycles).