bluuebunny/crossref_metadata_2025 huggingface dataset:
Elucidating the Effect of Nutritional Imbalances of N and K on the Infection of Verticillium dahliae in Olive
Authors: López-Moral Ana , Agustí-Brisach Carlos , Ruiz-Blancas Cristina , Antón-Domínguez Begoña I. , Alcántara Esteban , Trapero Antonio
Published: January 2022

The effect of mineral nutrition on wilt diseases has been previously reported in many herbaceous hosts, though such an effect on Verticillium wilt in olive (Olea europaea L.; VWO), caused by Verticillium dahliae, is still uncertain. Field observations reveal that nitrogen (N) excess or imbalances of N-potassium (K) favour VWO epidemics. However, this has yet to be demonstrated. Thus, the aim of this study was to evaluate the influences of nutritional imbalances of N and K in V. dahliae infection of olive. To this end, adjusted treatments with N excess (↑N+↑Na), K deficiency (↓K) and their combination (↑N+↑Na+↓K) were evaluated on the viability of V. dahliae microsclerotia (MS), as well as on disease development in olive plants. In parallel, the potential indirect effect of the treatments on the viability of conidia and MS of V. dahliae was evaluated through the stimuli of root exudates. Treatments ↑N+↑Na and ↑N+↑Na+↓K decreased MS germination and disease progress, whereas ↓K significantly increased both parameters. Root exudates from treated plants increased the conidia germination of V. dahliae but reduced the MS germination. The results of this study will be the basis for planning further research towards a better understanding of the effect of mineral nutrition on VWO.
Il Silenzio: The First Renaissance Oil Painting on Canvas from the Uffizi Museum Restored with a Safe, Green Antimicrobial Emulsion Based on Citrus aurantium var. amara Hydrolate and Cinnamomum zeylanicum Essential Oil
Authors: Minotti Debora , Vergari Lara , Proto Maria Rita , Barbanti Lorenzo , Garzoli Stefania , Bugli Francesca , Sanguinetti Maurizio , Sabatini Luigia , Peduzzi Alice , Rosato Roberto , Bellardi Maria Grazia , Mattarelli Paola , De Luca Daphne , Di Vito Maura
Published: January 2022

Preserving artworks from the attacks of biodeteriogens is a primary duty of humanity. Nowadays, restorers use chemicals potentially dangerous for both artworks and human health. The purpose of this work was to find a green and safe formulation based on natural substances with fungicidal activity to restore ancient oil paintings, particularly “Il Silenzio” (by Jacopo Zucchi) preserved at the Uffizi Museum in Florence, Italy. The study was divided into two phases. First phase (in vitro study): three essential oils (EOs) and four hydrolates (Hys) were analysed by GC-mass spectrometry and in vitro tested against six ATCC strains of molds. An emulsion based on the more active natural compounds was tested on aged and unaged canvases samples to evaluate both their fungicidal activity and the impact on chemical-physical parameters. Finally, an in vivo toxicity test performed on the Galleria mellonella model assessed the safety for health. Second phase (in situ application): the emulsion was sprayed on the back of the painting and left to act for 24 h. Biodeteriogens present on the “Il Silenzio” painting were microbiologically identified before and after the treatment. The emulsion formulated with C. zeylanicum EO and C. aurantium var. amara Hy showed the best antifungal activity both in vitro and in situ without altering the chemical-physical characteristics of paintings. Furthermore, no in vivo toxicity was shown. For the first time, a green antimicrobial emulsion based on Hy and EO, safe for operators, was used to decontaminate an artwork colonised by fungi before the restoration practices.
A Pragmatic Approach to Susceptibility Classification of Yeasts without EUCAST Clinical Breakpoints
Authors: Astvad Karen Marie Thyssen , Arikan-Akdagli Sevtap , Arendrup Maiken Cavling
Published: January 2022

EUCAST has established clinical breakpoints for the six most common Candida species and Cryptococcus neoformans but not for less common yeasts because sufficient evidence is lacking. Consequently, the question “How to interpret the MIC?” for other yeasts often arises. We propose a pragmatic classification for amphotericin B, anidulafungin, fluconazole, and voriconazole MICs against 30 different rare yeasts. This classification takes advantage of MIC data for more than 4000 isolates generated in the EUCAST Development Laboratory for Fungi validated by alignment to published EUCAST MIC data. The classification relies on the following two important assumptions: first, that when isolates are genetically related, pathogenicity and intrinsic susceptibility patterns may be similar; and second, that even if species are not phylogenetically related, the rare yeasts will likely respond to therapy, provided the MIC is comparable to that against wild-type isolates of more prevalent susceptible species because rare yeasts are most likely “rare” due to a lower pathogenicity. In addition, the treatment recommendations available in the current guidelines based on the in vivo efficacy data and clinical experience are taken into consideration. Needless to say, it is of utmost importance (a) to ascertain that the species identification is correct (using MALDI-TOF or sequencing), and (b) to re-test the isolate once or twice to confirm that the MIC is representative for the isolate (because of the inherent variability in MIC determinations). We hope this pragmatic guidance is helpful until evidence-based EUCAST breakpoints can be formally established.
Simple and Efficient Pressure Ulcer Reconstruction via Primary Closure Combined with Closed-Incision Negative Pressure Wound Therapy (CiNPWT)—Experience of a Single Surgeon
Authors: Hsu Kuo-Feng , Kao Li-Ting , Chu Pei-Yi , Chen Chun-Yu , Chou Yu-Yu , Huang Dun-Wei , Liu Ting-Hsuan , Tsai Sheng-Lin , Wu Chien-Wei , Hou Chih-Chun , Wang Chih-Hsin , Dai Niann-Tzyy , Chen Shyi-Gen , Tzeng Yuan-Sheng
Published: January 2022

Background: In this study, we aimed to analyze the clinical efficacy of closed-incision negative pressure wound therapy (CiNPWT) when combined with primary closure (PC) in a patient with pressure ulcers, based on one single surgeon’s experience at our medical center. Methods: We retrospectively reviewed the data of patients with stage III or IV pressure ulcers who underwent reconstruction surgery. Patient characteristics, including age, sex, cause and location of defect, comorbidities, lesion size, wound reconstruction methods, operation time, debridement times, application of CiNPWT to reconstructed wounds, duration of hospital stay, and wound complications were analyzed. Results: Operation time (38.16 ± 14.02 vs. 84.73 ± 48.55 min) and duration of hospitalization (36.78 ± 26.92 vs. 56.70 ± 58.43 days) were shorter in the PC + CiNPWT group than in the traditional group. The frequency of debridement (2.13 ± 0.98 vs. 2.76 ± 2.20 times) was also lower in the PC + CiNPWT group than in the traditional group. The average reconstructed wound size did not significantly differ between the groups (63.47 ± 42.70 vs. 62.85 ± 49.94 cm2), and there were no significant differences in wound healing (81.25% vs. 75.38%), minor complications (18.75% vs. 21.54%), major complications (0% vs. 3.85%), or mortality (6.25% vs. 10.00%) between the groups. Conclusions: Our findings indicate that PC combined with CiNPWT represents an alternative reconstruction option for patients with pressure ulcers, especially in those for whom prolonged anesthesia is unsuitable.
Acknowledgment to Reviewers of Journal of Risk and Financial Management in 2021
Authors:   JRFM Editorial Office
Published: January 2022

Rigorous peer-reviews are the basis of high-quality academic publishing [...]
Acknowledgment to Reviewers of JSAN in 2021
Authors:   JSAN Editorial Office
Published: January 2022

Rigorous peer-reviews are the basis of high-quality academic publishing [...]
Net Zero Energy Districts: Connected Intelligence for Carbon-Neutral Cities
Authors: Komninos Nicos
Published: January 2022

Net-Zero Energy Districts (NZEDs) are city districts in which the annual amount of CO2 emissions released is balanced by emissions removed from the atmosphere. NZEDs constitute a major component in a new generation of “smart-green cities”, which deploy both smart city technologies and renewable energy technologies. NZEDs promote environmental sustainability, contribute to cleaner environments and reduce global warming and the threats from climate change. This paper describes a model to assess the feasibility of the transition of city districts to self-sufficient NZEDs, based on locally produced renewable energy suitable for cities. It also aims to identify threshold conditions that allow for a city district to become a self-sufficient NZED using smart city systems, renewable energy, and nature-based solutions. The significance of transition to self-sufficient NZEDs is extremely important as it considerably decentralises and multiplies the efforts for carbon-neutral cities. The methodology we follow combines the literature review, model design, model feed with data, and many simulations to assess the outcome of the model in various climate, social, technology, and district settings. In the conclusion, we assess whether the transition to NZEDs with solar panel energy locally produced is feasible, we identify thresholds in terms of climate, population density, and solar conversion efficiency, and assess the compatibility of NZEDs with compact city planning principles.
User Perception of Public Parks: A Pilot Study Integrating Spatial Social Media Data with Park Management in the City of Chicago
Authors: Huang Yiwei , Li Zhixin , Huang Yuhan
Published: January 2022

User-generated content (UGC) is a relatively young field of research; however, it has been proven useful in disciplines such as hospitality and tourism, to elicit public opinions of place usage. In landscape architecture and urban planning, UGC has been used to understand people’s emotions and movement in a space, while other areas and additional functions are yet to be discovered. This paper explores the capability of UGC in revealing city-scale park management problems and the applicability of social media as a future tool in bridging visitor feedback to city parks and recreation department staff. This research analyzed the spatial characteristics and patterns of Google Maps review quantity, rating score, and review comments. The results of this pilot study indicate the spatial and structural features of the Chicago parks and demonstrate distribution problems, financial investment priority concerns, park usage characteristics, and user preferences of the park attributes. Findings affirm that user-generated online reviews can be used as an alternative and self-reporting data source to effectively assess the natural performance and users’ experience of city parks and can potentially serve as an evaluative tool for public park management.
Drone-Based Identification of Erosive Processes in Open-Pit Mining Restored Areas
Authors: Padró Joan-Cristian , Cardozo Johnsson , Montero Pau , Ruiz-Carulla Roger , Alcañiz Josep Maria , Serra Dèlia , Carabassa Vicenç
Published: January 2022

Unmanned Aerial Systems, or drones, are very helpful tools for managing open-pit mining operations and developing ecological restoration activities. This article presents a method for identifying water erosion processes in active quarries by means of drone imagery remote sensing, in the absence of pre-existing imagery or mapping for comparison. A Digital Elevation Model (DEM) with a spatial resolution (SR) >10 cm and an orthophoto with an SR >2.5 cm were generated from images captured with a drone and their subsequent photogrammetric processing. By using Geographical Information Systems tools to process the DEM, a detailed drainage network was obtained, the areas of detected water erosion were separated, and the watersheds in the gullies identified. Subsequently, an estimated DEM before the erosive processes was reconstructed by interpolating the gully ridges; this DEM serves as a reference for the relief before the erosion. To calculate the volume of eroded material, the DEM of Differences was calculated, which estimates the volume difference between the previously estimated DEM and the current DEM. Additionally, we calculated the material necessary for the geomorphological adaptation of the quarry and the slope map, which are two valuable factors closely related to the monitoring of erosive processes. The results obtained allowed us to identify the erosion factors quickly and accurately in this type of mining. In the case of water-filled quarries, it would be important to characterize the subsurface relief. Essentially, the presented method can be applied with affordable and non-invasive materials to create digital grid maps at 10 cm resolution, obtaining data ready for 3D metrics, being a very practical landscape modelling tool for characterizing the restoration evolution of open-pit mining spaces.
Combining MSPA-MCR Model to Evaluate the Ecological Network in Wuhan, China
Authors: Hu Chunguang , Wang Ziyi , Wang Yu , Sun Dongqi , Zhang Jingxiang
Published: January 2022

Rapid urbanization development and construction has seriously threatened the connectivity of habitat patches in cities and hindered the construction of ecological networks in highly urbanized areas. Among them, China is affected by early compressed urbanization, and the broken ecological space in cities and towns has attracted the extensive interest of researchers. To avoid the subjective randomness and single analysis of ecological space in urbanization areas, this paper takes the central urban area of Wuhan as the main research area. It comprehensively evaluates the ecological network space by combining the MSPA-MCR model. The main conclusions are as follows: (1) Identifying the ecological landscape types with important ecological significance in the study area: Core (88.29%), Islet (0.25%), Perf (0.63%), Edge (9.74%), Loop (0.22%), and Bridge (0.14%). Through the dPC landscape index, seven important ecological sources south of the middle reaches of the Yangtze River were identified. (2) According to the comprehensive factors of natural and human factors constructed by the MCR model, the minimum cumulative ecological resistance surface was established, with an average value of 2.65, a maximum value of 4.70, and a minimum value of 1.00, showing a trend that the ecological resistance values in the central and eastern parts are lower than those in the western part. (3) According to the standard deviation ellipse, the distribution direction of NE–SW in ecological sources was analyzed. The ecological sources distributed in the north were less, and the spatial distribution was scattered on the whole. The strong global positive correlation and local spatial aggregation characteristics of ecological resistance surface were evaluated according to spatial autocorrelation. Based on the gravity model, the interaction intensity of ecological corridors between source areas was evaluated, and the importance of ecological corridor protection and restoration was quantitatively analyzed. The research results provide scientific and reasonable references and a basis for ecological planning of Wuhan central city.
The Influence of the Organizational Culture of Andalusian Local Governments on the Localization of Sustainable Development Goals
Authors: Delgado-Baena Jesús , García-Serrano Juan de Dios , Toro-Peña Oscar , Vela-Jiménez Rocío
Published: January 2022

Local governments are key to establishing public policies linked to the 2030 Agenda. To achieve the Sustainable Development Goals (SDGs), public innovation is essential, and one of the essential pillars is transversality and partnerships (internal and external). This implies a transformative political, technical, and institutional culture that some authors have called, in the case of Andalusia, Spain, a “culture of solidarity”, as many of the elements of the 2030 Agenda are established within local organizations. This article aims to answer the question: Do Andalusian local authorities have an organizational culture and structure that facilitates the localization of the SDGs? To do so, it analyzes the conditioning factors, facilitators, and barriers that exist in local governments to advance in the mainstreaming of the localization and development processes of the 2030 Agenda in their territories. A study has been carried out on the perception of local technicians and the assessment of their own organization aligned with the 2030 Agenda. The results obtained indicate that local governments in Andalusia have made efforts to establish social actions and policies against poverty. The 2030 Agenda is perceived as an opportunity to transform local entities, with more open, collaborative, transversal, and interconnected institutions.
Acknowledgment to Reviewers of Land in 2021
Authors:   Land Editorial Office
Published: January 2022

Rigorous peer-reviews are the basis of high-quality academic publishing [...]
Lexical Category and Downstep in Japanese
Authors: Hirayama Manami , Hwang Hyun Kyung , Kato Takaomi
Published: January 2022

In pursuing the mapping between syntax and phonology/prosody, little attention has been paid to the kinds of syntactic information that can affect prosody. In this paper, we explore Japanese downstep, a process in phrasal phonology. What syntactic information affects downstep and what does not? Specifically, do lexical categories affect downstep? We investigate the effects of nouns, adjectives, and verbs in different syntactic settings (e.g., [X1 [X2 N]], [[X1 X2] N], predicative X) through production experiments. We found that adjectives in [X1 [X2 N]] may block downstep, whereas adjectives in other structures as well as nouns and verbs generally do not block it. We analyze this phonological patterning as being derivative of an interaction between syntactic structures and lexical categories.
Oral Reflection Tasks: Advanced Spanish L2 Learner Insights on Emergency Remote Teaching Assessment Practices in a Higher Education Context
Authors: Ducasse Ana Maria
Published: January 2022

This paper reports on a small-scale study that is the first to explore Advanced Spanish L2 learners’ personal awareness of their language and culture learning through e-assessment tasks in an Emergency Remote Teaching (ERT) context, mediated by five task-specific, individual spoken reflections. The value of reflection in education, particularly for L2 writing and distance learning, has been explored in different modalities, e.g., individual spoken reflection and group spoken reflection. Building on previous research, this study explores a group of advanced Spanish L2 learners (n = 25) reflecting on five multi-modal e-assessments through individually assessed oral audio-recorded post-assessment reflection tasks (n = 125). A thematic content analysis applied to transcriptions yields findings from a pedagogical perspective on language learning, completing assessments and personal affective responses. The learners’ candid and explicit orientations towards various types of multimodal language-learning e-assessment tasks offer instructors information on learners’ awareness of classroom-based assessment tasks being enablers for individual learning goals.
The Unaccompanied Child’s Right to Legal Assistance and Representation in Asylum Procedures under EU Law
Authors: Vannelli Marina
Published: January 2022

The independent migration of children today is a global phenomenon present in many regions worldwide, where unaccompanied minors seeking asylum do not enjoy full protection of their rights. Among their procedural safeguards, the right to legal assistance and representation is a fundamental right strictly related to the realization of other rights contained in the UN Convention on the Rights of the Child. Nevertheless, despite the fundamental role that guardians and legal advisors play in the wellbeing of unaccompanied children seeking asylum, many issues are currently affecting the exercise and implementation of this fundamental right in several European Union Member States. Therefore, the purpose of this article is to examine the content and scope of protection of this right under EU law, while highlighting the existence of possible ambiguities or gaps in current legal standards. Which EU law rules currently protect unaccompanied minors’ access to legal assistance? What changes are necessary in order to strengthen that protection for unaccompanied minors seeking asylum? These are some of the questions that this paper addresses in order to critically analyze the level of protection that Europe has provided to unaccompanied children’s right to legal assistance.
A 90-Day Safety Study of Meat from MSTN and FGF5 Double-Knockout Sheep in Wistar Rats
Authors: Zhao Yue , Chen Mingming , Li Yao , Xu Xueling , Wu Sujun , Liu Zhimei , Qi Shiyu , Yi Guang , Zhang Xiaosheng , Zhang Jinlong , Guo Xiaofei , Yu Kun , Deng Shoulong , Li Yan , Lian Zhengxing
Published: January 2022

MSTN and FGF5 gene knockout sheep generated by the CRISPR/Cas9 system exhibit the ‘double-muscle’ phenotype, and increased density and length of hairs, providing valuable new breeding material. In a previous study, we obtained MSTN and FGF5 double-knockout sheep of significant breeding value. In this study, we carried out a 90-day feeding study in Wistar rats to assess the safety of genome-edited mutton. Seven rat groups with 10 females and 10 males per group were fed different concentrations (3.75%, 7.5%, and 15%) of double-knockout mutton or wild-type mutton in a conventional commercial diet for 90 days. At the end of the feeding, routine urine and blood tests and measurements of blood biochemical indicators were performed. Furthermore, the major organs of each group of rats were weighed and examined histopathologically. Although there were significant differences among the groups in some parameters, all values were within the normal ranges. Therefore, the 90-day rat feeding study showed that the meat from MSTN and FGF5 double-knockout sheep did not have any long-term adverse effects on rat health. This study also provides valuable reference information for assessing the safety of meat from animals with knockout of multiple genes.
Impaired Mitochondrial Bioenergetics under Pathological Conditions
Authors: Nesci Salvatore , Lenaz Giorgio
Published: January 2022

Mitochondria are the powerhouses of cells; however, mitochondrial dysfunction causes energy depletion and cell death in various diseases [...]
Classification of Dystonia
Authors: di Biase Lazzaro , Di Santo Alessandro , Caminiti Maria Letizia , Pecoraro Pasquale Maria , Di Lazzaro Vincenzo
Published: January 2022

Dystonia is a hyperkinetic movement disorder characterized by abnormal movement or posture caused by excessive muscle contraction. Because of its wide clinical spectrum, dystonia is often underdiagnosed or misdiagnosed. In clinical practice, dystonia could often present in association with other movement disorders. An accurate physical examination is essential to describe the correct phenomenology. To help clinicians reaching the proper diagnosis, several classifications of dystonia have been proposed. The current classification consists of axis I, clinical characteristics, and axis II, etiology. Through the application of this classification system, movement disorder specialists could attempt to correctly characterize dystonia and guide patients to the most effective treatment. The aim of this article is to describe the phenomenological spectrum of dystonia, the last approved dystonia classification, and new emerging knowledge.
Pathomechanisms and Treatment Implications for Stroke in COVID-19: A Review of the Literature
Authors: Stamm Brian , Huang Deborah , Royan Regina , Lee Jessica , Marquez Joshua , Desai Masoom
Published: January 2022

Stroke in patients with COVID-19 has received increasing attention throughout the global COVID-19 pandemic, perhaps due to the substantial disability and mortality that can result when the two conditions co-occur. We reviewed the existing literature and found that the proposed pathomechanism underlying COVID-19-associated ischemic stroke is broadly divided into the following three categories: vasculitis, endothelialitis, and endothelial dysfunction; hypercoagulable state; and cardioembolism secondary to cardiac dysfunction. There has been substantial debate as to whether there is a causal link between stroke and COVID-19. However, the distinct phenotype of COVID-19-associated strokes, with multivessel territory infarcts, higher proportion of large vessel occlusions, and cryptogenic stroke mechanism, that emerged in pooled analytic comparisons with non-COVID-19 strokes is compelling. Further, in this article, we review the various treatment approaches that have emerged as they relate to the proposed pathomechanisms. Finally, we briefly cover the logistical challenges, such as delays in treatment, faced by providers and health systems; the innovative approaches utilized, including the role of tele-stroke; and the future directions in COVID-19-associated stroke research and healthcare delivery.
Analysis of Fluctuation in the Heme-Binding Pocket and Heme Distortion in Hemoglobin and Myoglobin
Authors: Kondo Hiroko X. , Takano Yu
Published: January 2022

Heme is located in the active site of proteins and has diverse and important biological functions, such as electron transfer and oxygen transport and/or storage. The distortion of heme porphyrin is considered an important factor for the diverse functions of heme because it correlates with the physical properties of heme, such as oxygen affinity and redox potential. Therefore, clarification of the relationship between heme distortion and the protein environment is crucial in protein science. Here, we analyzed the fluctuation in heme distortion in the protein environment for hemoglobin and myoglobin using molecular dynamics (MD) simulations and quantum mechanical (QM) calculations as well as statistical analysis of the protein structures of hemoglobin and myoglobin stored in Protein Data Bank. Our computation and statistical analysis showed that the protein environment for hemoglobin and myoglobin prominently affects the doming distortion of heme porphyrin, which correlates with its oxygen affinity, and that the magnitude of distortion is different between hemoglobin and myoglobin. These results suggest that heme distortion is affected by its protein environment and fluctuates around its fitted conformation, leading to physical properties that are appropriate for protein functions.
Whole Body MRI in the Detection of Lymph Node Metastases in Patients with Testicular Germ Cell Cancer
Authors: Pasoglou Vassiliki , Van Nieuwenhove Sandy , Van Damme Julien , Michoux Nicolas , Van Maanen Aline , Annet Laurence , Machiels Jean-Pascal , Tombal Bertrand , Lecouvet Frederic E.
Published: January 2022

Whole-Body Magnetic Resonance Imaging (WB-MRI) is increasingly used for metastatic screening in oncology. This prospective single center study assesses the diagnostic value of WB-MRI including diffusion weighted imaging (DWI) and identifies the sufficient protocol for metastatic lymph node detection in patients with testicular germ cell cancer (TGCC). Forty-three patients underwent contrast enhanced thoraco-abdominopelvic CT (TAP-CT) and WB-MRI with DWI for metastatic lymph node screening. Two independent readers reviewed CTs and WB-MRIs. The diagnostic performance of different imaging protocols (CT, complete WB-MRI, T1W + DWI, T2W + DWI), the agreement between these protocols and the reference standard, the reproducibility of findings and the image quality (Signal and contrast to Noise Ratios, Likert scale) were studied. Reproducibility was very good regardless of both lesion locations (retroperitoneal vs distant lymph nodes, other lesions) and the reader. Diagnostic accuracy of MRI was ≥95% (regardless of the locations and imaging protocol); accuracy of CT was ≥93%. There was a strict overlap of 95% CIs associated with this accuracy between complete WB-MRI, T1W + DWI and T2W + DWI, regardless of the reader. Higher Likert score and SNR were observed for DWI, followed by T2W and T1W sequences. In conclusion, a fast WB-MRI protocol including T2W and DWI is a sufficient, accurate, non-irradiating alternative to TAP-CT for metastatic lymph node screening in TGCC.
Crystal Structure and Concentration-Driven Phase Transitions in Lu(1−x)ScxFeO3 (0 ≤ x ≤ 1) Prepared by the Sol–Gel Method
Authors: Pakalniškis Andrius , Alikin Denis O. , Turygin Anton P. , Zhaludkevich Alexander L. , Silibin Maxim V. , Zhaludkevich Dmitry V. , Niaura Gediminas , Zarkov Aleksej , Skaudžius Ramūnas , Karpinsky Dmitry V. , Kareiva Aivaras
Published: January 2022

The structural state and crystal structure of Lu(1−x)ScxFeO3 (0 ≤ x ≤ 1) compounds prepared by a chemical route based on a modified sol–gel method were investigated using X-ray diffraction, Raman spectroscopy, as well as scanning electron microscopy. It was observed that chemical doping with Sc ions led to a structural phase transition from the orthorhombic structure to the hexagonal structure via a wide two-phase concentration region of 0.1 < x < 0.45. An increase in scandium content above 80 mole% led to the stabilization of the non-perovskite bixbyite phase specific for the compound ScFeO3. The concentration stability of the different structural phases, as well as grain morphology, were studied depending on the chemical composition and synthesis conditions. Based on the data obtained for the analyzed samples, a composition-dependent phase diagram was constructed.
In Situ Ti6Al4V/TiB Composites Prepared by Hydrogen-Assisted Sintering of Blends Containing TiH2 and Ball-Milled Ti+TiB2 Powders
Authors: Song Yuchao , Qiu Fucheng , Savvakin Dmytro , Xu Xiaofeng , Stasiuk Oleksandr , Ivasishin Orest , Cheng Tuo
Published: January 2022

In the present study, 98.6–99.5% dense in situ reinforced Ti6Al4V/TiB composites were manufactured with a newly developed approach based on hydrogen-assisted blended elemental powder metallurgy (BEPM). The approach includes the activation milling of titanium powder produced with hydrogenation-dehydrogenation (HDH-Ti powder) with finer TiB2 additives, following blending with TiH2 and master alloy (MA) powders, and final press-and-sinter operations. Scanning electron microscope (SEM) observations prove the formation of microstructures with improved density and homogeneous distribution of TiB reinforcements in a sintered Ti6Al4V matrix. Hardness and compressive tests validated the high mechanical characteristics of produced composites. The effect of preliminary milling time over 2–6 h and the ratio of hydrogenated and non-hydrogenated titanium powders used (TiH2 vs. HDH Ti) on microstructure and mechanical properties were studied to further optimize the processing parameters. Test results indicate the above approach can be regarded as a promising route for the cost-effective manufacturing of Ti6Al4V/TiB composite with reduced porosity, tailored microstructure uniformity, acceptable impurity level and, hence, mechanical characteristics sufficient for practice applications.
Nanostructure and Morphology of the Surface as Well as Micromechanical and Sclerometric Properties of Al2O3 Layers Subjected to Thermo-Chemical Treatment
Authors: Bara Marek , Niedźwiedź Mateusz , Skoneczny Władysław , Barylski Adrian
Published: January 2022

The article presents the effect of the thermo-chemical treatment of Al2O3 layers on their nanostructure, surface morphology, chemical composition as well as their micromechanical and sclerometric properties. Oxide layers were produced on EN AW-5251 aluminium alloy (AlMg2) by the method of direct current anodizing in a three-component electrolyte. The thermo-chemical treatment was carried out in distilled water and aqueous solutions of Na2SO4·10H2O and Na2Cr2O7·2H2O. It was shown that the thermo-chemical treatment process changes the morphology of the surface of the layers (the formation of a sub-layer from the Na2SO4·10H2O and Na2Cr2O7·2H2O solutions), which directly increases the thickness of the layers by 0.37 and 1.77 µm, respectively. The thermo-chemical treatment in water also resulted in the formation of a 0.63 µm thick sub-layer. The micromechanical tests indicated a rise in the surface microhardness of the layers in the case of their thermo-chemical treatment in water and the Na2SO4·10H2O solution and a decrease in the case of the layers modified in the Na2Cr2O7·2H2O solution. The highest microhardness (7.1 GPa) was exhibited by the layer modified in the Na2SO4·10H2O solution. Scratch tests demonstrated that the thermo-chemically treated layers had better adhesive properties than the reference layer. The best scratch resistance was exhibited by the layer after thermo-chemical treatment in the Na2SO4·10H2O solution (the highest values, practically for all the critical loads) which, together with its low roughness and high load capacity, predispose it to sliding contacts.
Radiative Thermal Effects in Large Scale Additive Manufacturing of Polymers: Numerical and Experimental Investigations
Authors: Cosson Benoît , Akué Asséko André Chateau , Pelzer Lukas , Hopmann Christian
Published: January 2022

The present paper addresses experimental and numerical investigations of a Large Scale Additive Manufacturing (LSAM) process using polymers. By producing large components without geometrical constraints quickly and economically, LSAM processes have the capability to revolutionize many industries. Accurate prediction and control of the thermal history is key for a successful manufacturing process and for achieving high quality and good mechanical properties of the manufactured part. During the LSAM process, the heat emitted by the nozzle leads to an increase in the temperature of the previously deposited layer, which prepares the surface for better adhesion of the new layer. It is therefore necessary to take into account this part of heat source in the transient heat transfer equation to correctly and completely describe the process and predict the temperature field of the manufactured part. The present study contributes to experimental investigations and numerical analysis during the LSAM process. During the process, two types of measurements are performed: firstly, the heat emitted by the nozzle is measured via a radiative heat sensor; secondly, the temperature field is measured using an infrared camera while varying the process speed. At the same time, a numerical simulation model is developed in order to validate the experimental results. The temperature fields of the manufactured parts computed by numerical simulations are in very good agreement with the temperature fields measured by infrared thermograph with the contribution of the nozzle’s heat exchange.
Bacterial Cellulose—A Remarkable Polymer as a Source for Biomaterials Tailoring
Authors: Popa Lăcrămioara , Ghica Mihaela Violeta , Tudoroiu Elena-Emilia , Ionescu Diana-Georgiana , Dinu-Pîrvu Cristina-Elena
Published: January 2022

Nowadays, the development of new eco-friendly and biocompatible materials using ‘green’ technologies represents a significant challenge for the biomedical and pharmaceutical fields to reduce the destructive actions of scientific research on the human body and the environment. Thus, bacterial cellulose (BC) has a central place among these novel tailored biomaterials. BC is a non-pathogenic bacteria-produced polysaccharide with a 3D nanofibrous structure, chemically identical to plant cellulose, but exhibiting greater purity and crystallinity. Bacterial cellulose possesses excellent physicochemical and mechanical properties, adequate capacity to absorb a large quantity of water, non-toxicity, chemical inertness, biocompatibility, biodegradability, proper capacity to form films and to stabilize emulsions, high porosity, and a large surface area. Due to its suitable characteristics, this ecological material can combine with multiple polymers and diverse bioactive agents to develop new materials and composites. Bacterial cellulose alone, and with its mixtures, exhibits numerous applications, including in the food and electronic industries and in the biotechnological and biomedical areas (such as in wound dressing, tissue engineering, dental implants, drug delivery systems, and cell culture). This review presents an overview of the main properties and uses of bacterial cellulose and the latest promising future applications, such as in biological diagnosis, biosensors, personalized regenerative medicine, and nerve and ocular tissue engineering.
The Use of Chitosan and Starch-Based Flocculants for Filter Backwash Water Treatment
Authors: Maćczak Piotr , Kaczmarek Halina , Ziegler-Borowska Marta , Węgrzynowska-Drzymalska Katarzyna , Burkowska-But Aleksandra
Published: January 2022

Inorganic aluminum or iron salts supported with synthetic polymers are commonly used to eradicate colloidal particles from water in coagulation and flocculation processes. Nevertheless, these agents have several disadvantages, such as large volumes of sludge produced or environmental toxicity. Recently biodegradable polymers have been suggested as eco-friendly flocculants for water treatment. This study aimed to investigate the possibilities of using starch and chitosan and their oxidized derivatives as flocculants for filter backwash water treatment. Dialdehyde starch (DST) and dialdehyde chitosan (DCT) were synthesized by periodate oxidization of natural starch from corn and low molecular weight chitosan. The obtained materials have been characterized with scanning electron microscopy (SEM), ATR-FTIR spectroscopy, and thermogravimetric analysis (TGA). Furthermore, we studied the flocculation properties of polysaccharide flocculants in a series of jar tests. The effectiveness of chitosan and starched-based flocculants was compared to synthetic polymers commonly used to treat iron ions-rich filter backwash water. The environmental aspects of these chemicals, particularly the biodegradability of post-flocculation residues, were also addressed. It was found that oxidized starch and chitosan derivatives can be used as ecological flocculating materials to treat potable water or sludge.
Microstructure Evolution and Dynamic Recrystallization Behavior of Mg-Gd-Y-Zn-Zr Alloy during Rotating Backward Extrusion
Authors: Duan Yali , Yu Jianmin , Dong Beibei , Zhang Huifang , Meng Mu , Cheng Mei , Zhang Zhimin , Zhang Baohong , Hao Hongyuan , Xu Ping , Liu Huiling
Published: January 2022

Rotating backward extrusion (RBE) is one of severe plastic deformation (SPD) methods used to produce cylindrical components with a very large strain by a single pass. In this study, the microstructure and texture evolution in the different regions of Mg-12Gd-4Y-2Zn-0.5Zr (wt.%) alloys via RBE process were investigated by using optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM) and electron back-scatter diffraction (EBSD). The results showed that the cup-shaped sample formed by RBE process exhibited typical gradient microstructure expanding from its inner wall to outer wall along the radial direction (RD). The average grain size of the RBEed sample decreased when the radius decreased from the edge region to the center region along the RD, which was attributed to the different strains and strain rates in the different regions. It also could be observed that the center region showed highest deformation and the edge region exhibited the lowest deformation in the RBEed sample along the RD. In addition, the grain refinement mechanisms of the experimental alloy containing long-period stacking ordered (LPSO) phases after RBE with 100 N were continuous dynamic recrystallization (CDRX), discontinuous dynamic recrystallization (DDRX) and particle stimulated nucleation (PSN).
Synthesis and Photoluminescence Properties of Pr3+-Doped Ba0.5Ca0.5TixZr(1-x)O3 Perovskite Diphasic Ceramics Obtained by the Modified Pechini Method
Authors: Wilk Agnieszka , Kozielski Lucjan , Michalik Daniel , Kozień Dawid , Makowska Jolanta , Pędzich Zbigniew
Published: January 2022

The Pr3+-doped solid solutions from (Ba,Ca)(Ti,Zr)O3 (BCTZO) system were successfully synthesized using an efficient and low-energy consuming route—the Pechini method combined with the sintering at relatively low temperature (1450 °C). The obtained materials were characterized by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The dielectric properties were systematically studied. The Pr3+-doped BCTZO diphasic material generates intense and broad red photoluminescence (PL) emission at room temperature. The optical properties were significantly improved with the Ti4+ substitution by Zr4+ ions. As a result, the Pr3+-doped (Ba,Ca)(Ti,Zr)O3 ceramics is a promising candidate for environmentally friendly, multifunctional material by combining good dielectric and photoluminescent properties with prognosis for the manifestation of strong photoluminescent and mechanoluminescent effects.
Influence of the hBN Dielectric Layers on the Quantum Transport Properties of MoS2 Transistors
Authors: Fiore Sara , Klinkert Cedric , Ducry Fabian , Backman Jonathan , Luisier Mathieu
Published: January 2022

The encapsulation of single-layer 2D materials within hBN has been shown to improve the mobility of these compounds. Nevertheless, the interplay between the semiconductor channel and the surrounding dielectrics is not yet fully understood, especially their electron–phonon interactions. Therefore, here, we present an ab initio study of the coupled electrons and phonon transport properties of MoS2-hBN devices. The characteristics of two transistor configurations are compared to each other: one where hBN is treated as a perfectly insulating, non-vibrating layer and one where it is included in the ab initio domain as MoS2. In both cases, a reduction of the ON-state current by about 50% is observed as compared to the quasi-ballistic limit. Despite the similarity in the current magnitude, explicitly accounting for hBN leads to additional electron–phonon interactions at frequencies corresponding to the breathing mode of the MoS2-hBN system. Moreover, the presence of an hBN layer around the 2D semiconductor affects the Joule-induced temperature distribution within the transistor.
Quantification of Ceramsite Granules in Lightweight Concrete Panels through an Image Analysis Technique
Authors: Bu Changming , Yang Haiyan , Liu Lei , Zhu Dongxu , Sun Yi , Yu Linwen , Ouyang Yuhui , Cao Xuemei , Wei Qike
Published: January 2022

Ceramsite particles are an important component of lightweight ceramsite concrete wall panels, and the density of the aggregate is much lower than the density of the slurry. It is generally accepted that there are inhomogeneities in the distribution of ceramsite particles in wall panels. Ceramsite concrete wallboard material is a research hotspot in the field of fabricated building materials at home and abroad; however, there is no effective way to quantify their inhomogeneity. Based on the application of image recognition technology in concrete homogeneity, a method to quantitatively evaluate the distribution of light aggregates in wall panels was developed. Three commercial lightweight vitrified concrete wall panels were cut into 324 cubes. The four cut surfaces of each specimen were photographed to analyze the proportion of ceramsite particle area, while the density, ultrasonic pulse velocity, and compressive strength of the specimens were tested. The results demonstrated that the image analysis method could effectively describe the homogeneity of the panels. The proportion of particle area of aggregate in the section of the cube had a strong correlation with the compressive strength, ultrasonic pulse velocity, and density, and there was an obvious linear relationship with the height of the plate where the cube was located. Based on this, the correlation equations of the proportion of particle area of aggregate, density, ultrasonic pulse velocity, compressive strength, and the height where the specimen was located were proposed. The quantitative parameters of the relevant properties of the wall panels were also obtained: the maximum difference between the proportion of particle area of the aggregate was 24%, the maximum difference between the density at the top and bottom of the wall panels was 115 kg/m3, and the maximum difference in the strength reached 5 MPa.
Eutectic Phase Characterization and Mechanical Properties of Al-Cu Alloy Ingot Solidified with Ultrasonic Treatment
Authors: Li Ruiqing , Dong Fang , Zhang Yun , Chen Pinghu , Li Xiaoqian
Published: January 2022

An Al-Cu alloy ingot was produced with the application of ultrasonic melt treatment. The effects of ultrasonication on the grain structure, eutectic phase, solution, and tensile properties of the alloy were analyzed. The volume and distribution of the eutectic phase were quantitatively evaluated based on stereological theory. The results are as follows: The grain-refinement efficiency at the center, 1/2 radius and edge of the ingot is 33.99%, 45.2% and 41.68%, respectively, under the action of an ultrasonic field. Ultrasonics improves the solid solubility of the Al-Cu alloy element, in which the solid solubility of Cu increases from 0.85% to 1.42%. The ultrasonic field improves the dispersion degree of the eutectic phase and reduces the volume fraction and eutectic phase number per unit volume. The mechanical properties of the Al-Cu alloy were improved by an ultrasonic field.
Influence of Gas-Flow Conditions on the Evolution of Thermally Insulating Si3N4 Nano-Felts
Authors: Santhosh Balanand , Biesuz Mattia , Zambotti Andrea , Sorarù Gian Domenico
Published: January 2022

This paper discusses the role of nitrogen (N2) gas flow conditions on the formation of silicon nitride (Si3N4) nano-felts from polysiloxane-impregnated polyurethane (PU) foams. The polymeric foam was converted into an amorphous silicon oxycarbide (SiOC) artefact during pyrolysis, which was then transformed, at a higher temperature, into a Si3N4 felt through a reaction between the decomposition products of SiOC with N2. The study identified that a N2 flux of ~2.60 cm.min−1 at the cross-section of the furnace (controlled to 100 cm3.min−1 at the inlet of the furnace using a flowmeter) substantially favored the transformation of the parent SiOC foam to Si3N4 felts. This process intensification step significantly reduced the wastage and the energy requirement while considering the material production on a bulk scale. The study also inferred that the cell sizes of the initial PU templates influenced the foam to felt transformation.