bluuebunny/crossref_metadata_2025 huggingface dataset:
Type I Interferon-Mediated Regulation of Antiviral Capabilities of Neutrophils
Authors: Stegelmeier Ashley A. , Darzianiazizi Maedeh , Hanada Kiersten , Sharif Shayan , Wootton Sarah K. , Bridle Byram W. , Karimi Khalil
Published: April 2021

Interferons (IFNs) are induced by viruses and are the main regulators of the host antiviral response. They balance tissue tolerance and immune resistance against viral challenges. Like all cells in the human body, neutrophils possess the receptors for IFNs and contribute to antiviral host defense. To combat viruses, neutrophils utilize various mechanisms, such as viral sensing, neutrophil extracellular trap formation, and antigen presentation. These mechanisms have also been linked to tissue damage during viral infection and inflammation. In this review, we presented evidence that a complex cross-regulatory talk between IFNs and neutrophils initiates appropriate antiviral immune responses and regulates them to minimize tissue damage. We also explored recent exciting research elucidating the interactions between IFNs, neutrophils, and severe acute respiratory syndrome-coronavirus-2, as an example of neutrophil and IFN cross-regulatory talk. Dissecting the IFN-neutrophil paradigm is needed for well-balanced antiviral therapeutics and development of novel treatments against many major epidemic or pandemic viral infections, including the ongoing pandemic of the coronavirus disease that emerged in 2019.
Bootstrapping and Pinning down the Root Meristem; the Auxin–PLT–ARR Network Unites Robustness and Sensitivity in Meristem Growth Control
Authors: Rutten Jacob P. , Ten Tusscher Kirsten H.
Published: April 2021

After germination, the meristem of the embryonic plant root becomes activated, expands in size and subsequently stabilizes to support post-embryonic root growth. The plant hormones auxin and cytokinin, together with master transcription factors of the PLETHORA (PLT) family have been shown to form a regulatory network that governs the patterning of this root meristem. Still, which functional constraints contributed to shaping the dynamics and architecture of this network, has largely remained unanswered. Using a combination of modeling approaches we reveal how the interplay between auxin and PLTs enables meristem activation in response to above-threshold stimulation, while its embedding in a PIN-mediated auxin reflux loop ensures localized PLT transcription and thereby, a finite meristem size. We furthermore demonstrate how this constrained PLT transcriptional domain enables independent control of meristem size and division rates, further supporting a division of labor between auxin and PLT. We subsequently reveal how the weaker auxin antagonism of the earlier active Arabidopsis response regulator 12 (ARR12) may arise from the absence of a DELLA protein interaction domain. Our model indicates that this reduced strength is essential to prevent collapse in the early stages of meristem expansion while at later stages the enhanced strength of Arabidopsis response regulator 1 (ARR1) is required for sufficient meristem size control. Summarizing, our work indicates that functional constraints significantly contribute to shaping the auxin–cytokinin–PLT regulatory network.
Role of Choline in Ocular Diseases
Authors: Hwang Jin-Sun , Shin Young-Joo
Published: April 2021

Choline is essential for maintaining the structure and function of cells in humans. Choline plays an important role in eye health and disease. It is a precursor of acetylcholine, a neurotransmitter of the parasympathetic nervous system, and it is involved in the production and secretion of tears by the lacrimal glands. It also contributes to the stability of the cells and tears on the ocular surface and is involved in retinal development and differentiation. Choline deficiency is associated with retinal hemorrhage, glaucoma, and dry eye syndrome. Choline supplementation may be effective for treating these diseases.
Genome-Wide Analysis Identified a Set of Conserved lncRNAs Associated with Domestication-Related Traits in Rice
Authors: He Huang , Zhou Yan-Fei , Yang Yu-Wei , Zhang Zhi , Lei Meng-Qi , Feng Yan-Zhao , Zhang Yu-Chan , Chen Yue-Qin , Lian Jian-Ping , Yu Yang
Published: April 2021

Crop domestication, which gives rise to a number of desirable agronomic traits, represents a typical model system of plant evolution. Numerous genomic evidence has proven that noncoding RNAs such as microRNAs and phasiRNAs, as well as protein-coding genes, are selected during crop domestication. However, limited data shows plant long noncoding RNAs (lncRNAs) are also involved in this biological process. In this study, we performed strand-specific RNA sequencing of cultivated rice Oryza sativa ssp. japonica and O. sativa ssp. indica, and their wild progenitor O. rufipogon. We identified a total of 8528 lncRNAs, including 4072 lncRNAs in O. rufipogon, 2091 lncRNAs in japonica rice, and 2365 lncRNAs in indica rice. The lncRNAs expressed in wild rice were revealed to be shorter in length and had fewer exon numbers when compared with lncRNAs from cultivated rice. We also identified a number of conserved lncRNAs in the wild and cultivated rice. The functional study demonstrated that several of these conserved lncRNAs are associated with domestication-related traits in rice. Our findings revealed the feature and conservation of lncRNAs during rice domestication and will further promote functional studies of lncRNAs in rice.
High Temperatures Decrease the Flight Capacity of Diaphorina citri Kuwayama (Hemiptera: Liviidae)
Authors: Antolinez Carlos A. , Moyneur Tobias , Martini Xavier , Rivera Monique J.
Published: April 2021

Diaphorina citri Kuwayama (Hemiptera: Liviidae), commonly known as Asian citrus psyllid (ACP), is an invasive insect pest and the vector of the bacterium causing Huanglongbing (HLB), a lethal disease of citrus. In the United States, ACP has been established in all citrus-producing zones, all of which have different environmental conditions. The spread of ACP and, more importantly, HLB, has progressed differently depending on the state, with more rapid spread in Florida and Texas than in California. Climatic variations between the regions are likely a strong factor in the difference in the rate of spread. Despite this, it is unknown how the flight capacity of D. citri is influenced by high temperatures (>30 °C) and subsequently, low humidity experienced in California but not in Texas or Florida. In this study, by using a custom-made, temperature-controlled flight mill arena, we assessed the effect of high temperatures on the flight capacity and flight propensity of D. citri under low (20–40%) and high (76–90%) relative humidity conditions. We found that temperature and humidity influence the propensity to engage in short or long-distance flight events. Psyllids exposed to temperatures above 43 °C only performed short flights (˂60 s), and a high relative humidity significantly decrease the proportion of long flights (≥60 s) at 26 and 40 °C. The flight capacity for insects who engaged in short and long flights was significantly affected by temperature but not by humidity. For long flyers, temperature (in the 26–43 °C range) was negatively correlated with distance flown and flight duration. The most favorable temperature for long dispersion was 26 °C, with suboptimal temperatures in the range of 32–37 °C and the least favorable temperatures at 40 and 43 °C. In conclusion, D. citri is able to fly in a broad range of temperatures and efficiently fly in high and low humidity. However, temperatures above 40 °C, similar to those experienced in semi-arid environments like Southern California or Arizona, are detrimental for its flight capacity.
Regulation of Cardiac Conduction and Arrhythmias by Ankyrin/Spectrin-Based Macromolecular Complexes
Authors: Nassal Drew , Yu Jane , Min Dennison , Lane Cemantha , Shaheen Rebecca , Gratz Daniel , Hund Thomas J.
Published: April 2021

The cardiac conduction system is an extended network of excitable tissue tasked with generation and propagation of electrical impulses to signal coordinated contraction of the heart. The fidelity of this system depends on the proper spatio-temporal regulation of ion channels in myocytes throughout the conduction system. Importantly, inherited or acquired defects in a wide class of ion channels has been linked to dysfunction at various stages of the conduction system resulting in life-threatening cardiac arrhythmia. There is growing appreciation of the role that adapter and cytoskeletal proteins play in organizing ion channel macromolecular complexes critical for proper function of the cardiac conduction system. In particular, members of the ankyrin and spectrin families have emerged as important nodes for normal expression and regulation of ion channels in myocytes throughout the conduction system. Human variants impacting ankyrin/spectrin function give rise to a broad constellation of cardiac arrhythmias. Furthermore, chronic neurohumoral and biomechanical stress promotes ankyrin/spectrin loss of function that likely contributes to conduction disturbances in the setting of acquired cardiac disease. Collectively, this review seeks to bring attention to the significance of these cytoskeletal players and emphasize the potential therapeutic role they represent in a myriad of cardiac disease states.
Long-Acting Reversible Contraception: Placement, Continuation, and Removal Rates at an Inner-City Academic Medical Center Clinic
Authors: Runyan Aliye , Welch Robert A. , Kramer Katherine J. , Cortez Sarah , Roberts LeAnne J. , Asamoah Clementina , Ottum Sarah , Sanders Jessica , Shafi Adib , Recanati Maurice-Andre
Published: April 2021

Long-Acting Reversible Contraception (LARCs) has the potential to decrease unintended pregnancies but only if women can easily access a requested method. Retrospective electronic chart review identified women desiring LARC placement over a one-year period ending 31 December 2016. Most of the 311 insertions were for family planning, with 220 new insertions and 60 replacements. Delays occurred in 38% (n = 118) of patients, averaged 5 ± 5 weeks, and 47% received interval contraception. Reasons included absence of qualified provider (n = 44, 37%), pending cultures (n = 31, 26%), and Mirena availability. Teenage LARC use favored Nexplanon whereas older women preferred Mirena (p < 0.01). Of the 11% choosing early LARC removal, a significant number were African Americans (p = 0.040) or teenagers (p = 0.048). Retention time varied by device type; most patients switched to other contraceptives. No patients experienced IUD expulsion. Understanding barriers, attempting to remedy them, and addressing the side effects associated with LARC use is of importance in this inner-city patient population in the United States.
Resistance to Immune Checkpoint Inhibitors Secondary to Myeloid-Derived Suppressor Cells: A New Therapeutic Targeting of Haematological Malignancies
Authors: Olivares-Hernández Alejandro , Figuero-Pérez Luis , Terán-Brage Eduardo , López-Gutiérrez Álvaro , Velasco Álvaro Tamayo , Sarmiento Rogelio González , Cruz-Hernández Juan Jesús , Miramontes-González José Pablo
Published: April 2021

Myeloid-derived suppressor cells (MDSCs) are a set of immature myeloid lineage cells that include macrophages, granulocytes, and dendritic cell precursors. This subpopulation has been described in relation to the tumour processes at different levels, including resistance to immunotherapy, such as immune checkpoint inhibitors (ICIs). Currently, multiple studies at the preclinical and clinical levels seek to use this cell population for the treatment of different haematological neoplasms, together with ICIs. This review addresses the different points in ongoing studies of MDSCs and ICIs in haematological malignancies and their future significance in routine clinical practice.
Bispecific Antibodies: A Review of Development, Clinical Efficacy and Toxicity in B-Cell Lymphomas
Authors: Salvaris Ross , Ong Jeremy , Gregory Gareth P.
Published: April 2021

The treatment landscape of B-cell lymphomas is evolving with the advent of novel agents including immune and cellular therapies. Bispecific antibodies (bsAbs) are molecules that recognise two different antigens and are used to engage effector cells, such as T-cells, to kill malignant B-cells. Several bispecific antibodies have entered early phase clinical development since the approval of the CD19/CD3 bispecific antibody, blinatumomab, for relapsed/refractory acute lymphoblastic leukaemia. Novel bsAbs include CD20/CD3 antibodies that are being investigated in both aggressive and indolent non-Hodgkin lymphoma with encouraging overall response rates including complete remissions. These results are seen even in heavily pre-treated patient populations such as those who have relapsed after chimeric antigen receptor T-cell therapy. Potential toxicities include cytokine release syndrome, neurotoxicity and tumour flare, with a number of strategies existing to mitigate these risks. Here, we review the development of bsAbs, their mechanism of action and the different types of bsAbs and how they differ in structure. We will present the currently available data from clinical trials regarding response rates, progression free survival and outcomes across a range of non-Hodgkin lymphoma subtypes. Finally, we will discuss the key toxicities of bsAbs, their rates and management of these adverse events.
Influence of the Depth of the Convolutional Neural Networks on an Artificial Intelligence Model for Diagnosis of Orthognathic Surgery
Authors: Kim Ye-Hyun , Park Jae-Bong , Chang Min-Seok , Ryu Jae-Jun , Lim Won Hee , Jung Seok-Ki
Published: April 2021

The aim of this study was to investigate the relationship between image patterns in cephalometric radiographs and the diagnosis of orthognathic surgery and propose a method to improve the accuracy of predictive models according to the depth of the neural networks. The study included 640 and 320 patients requiring non-surgical and surgical orthodontic treatments, respectively. The data of 150 patients were exclusively classified as a test set. The data of the remaining 810 patients were split into five groups and a five-fold cross-validation was performed. The convolutional neural network models used were ResNet-18, 34, 50, and 101. The number in the model name represents the difference in the depth of the blocks that constitute the model. The accuracy, sensitivity, and specificity of each model were estimated and compared. The average success rate in the test set for the ResNet-18, 34, 50, and 101 was 93.80%, 93.60%, 91.13%, and 91.33%, respectively. In screening, ResNet-18 had the best performance with an area under the curve of 0.979, followed by ResNets-34, 50, and 101 at 0.974, 0.945, and 0.944, respectively. This study suggests the required characteristics of the structure of an artificial intelligence model for decision-making based on medical images.
Transient Response of Olaparib on Pulmonary Artery Sarcoma Harboring Multiple Homologous Recombinant Repair Gene Alterations
Authors: Wu Chiao-En , Ng Ca Tung , Tan Kien Thiam
Published: April 2021

Primary pulmonary artery sarcoma (PPAS) is a rare malignancy arising from mesenchymal pulmonary artery cells and mimics pulmonary embolism. Palliative chemotherapy such as anthracycline- or ifosfamide-based regimens and targeted therapy are the only options. However, the evidence of clinically beneficial systemic treatment is scarce. Here, we report a case of disseminated PPAS achieving clinical tumor response to olaparib based on comprehensive genetic profiling (CGP) showing genetic alterations involving DNA repair pathway. This provides supportive evidence that olaparib could be a promising therapeutic agent for patients with disseminated PPAS harboring actionable haploinsufficiency of DNA damage repair (DDR).
Transformation of the Landscape in the Conditions of the Slovak Republic for Tourism
Authors: Oremusová Daša , Nemčíková Magdaléna , Krogmann Alfred
Published: April 2021

Tourism is one of the most dynamic sectors of the economy in Slovakia. With the orientation of localities to tourism, the landscape transformation is reflected in several positive and negative changes in the landscape. The aim of the contribution is to highlight the transformation processes leading to the creation of a tourist landscape in six selected localities in Slovakia. When selecting sites, we applied criteria such as the diversity of the original use, size or attractiveness. The environmental, socio-cultural and economic impacts of tourism on the landscape of localities were valuable in terms of sustainable development principles. From the methodological point of view, the primary methodology was the drivers–pressures–state–impact–response (DPSIR) model, used for integrated environmental assessment and the life cycle methodology of a tourism center with integrated sustainable development indicators. In the work results, based on the analysis of the historical development and the current state of localities, we evaluate their phase of the life cycle and the effects of tourism on the environment. We also present the possibilities of further development and heading direction of localities from point of view of tourism while pointing out the benefits and risks connected with the planned development.
Transport Accessibility in a Suburban Zone and Its Influence on the Local Real Estate Market: A Case Study of the Olsztyn Functional Urban Area (Poland)
Authors: Szczepańska Agnieszka
Published: April 2021

The development of real estate markets in the vicinity of cities is linked with suburbanization processes. The migration of the population to suburban areas contributes to the growth of the residential property market (houses, apartments and construction plots). To minimize commuting costs, property buyers opt for locations that are situated close to the urban core. This article analyzes construction plots on the local real estate market in the Olsztyn Functional Urban Area, in terms of their temporal accessibility and demographic changes. Spatial variations in population distribution were analyzed with the use of the Gini index and geostatistical interpolation techniques. Spearman’s rank correlation coefficient was calculated to determine the relationships between the analyzed variables. The study revealed differences in the spatial distribution of the population and real estate transactions as well as strong correlations between average transaction price, number of transactions, commuting time and population. The highest number of transactions were observed in cadastral districts situated in the direct vicinity of Olsztyn’s administrative boundaries and the major transportation routes due to their high temporal accessibility.
The Anti-Ageing and Whitening Potential of a Cosmetic Serum Containing 3-O-ethyl-l-ascorbic Acid
Authors: Zerbinati Nicola , Sommatis Sabrina , Maccario Cristina , Di Francesco Serena , Capillo Maria Chiara , Rauso Raffaele , Herrera Martha , Bencini Pier Luca , Guida Stefania , Mocchi Roberto
Published: April 2021

Skin ageing has many manifestations such as wrinkles, dryness, hyperpigmentation, and uneven skin tone. Extrinsic and intrinsic factors, especially solar ultraviolet light (UVB), contribute to skin ageing; its main features are brown spots, alterations in melanin pigmentation, and a decrease in collagen and hyaluronic acid linked to oxidative stress. Several studies showed that topical products containing ingredients with antioxidant activity can reduce oxidative damage; to provide a maximum anti-ageing effect to the skin, topical products can combine various ingredients. C-SHOT SERUM contains a combination of two molecules with a proven anti-ageing activity: a high percentage (30%) of a more stable vitamin C derivative, 3-O-ethyl-l-ascorbic acid, and lactic acid (1%). The product showed a high biocompatibility, assessed through an MTT assay on keratinocytes and on Reconstructed Human Epidermis (RHE, SkinEthic); the anti-ageing activity was demonstrated on human dermal fibroblasts and keratinocytes by a statistically significant increase in collagen production and a reduction of a UVB-induced DNA damage marker (γ-H2AX histone), indicating DNA protection. Moreover, a depigmenting activity, shown by a highly significant decrease in melanin content on treated Reconstructed Human Pigmented Epidermis (RHPE), was assessed. According to the data of our study, the tested product contrasts the effect of skin ageing and irregular pigmentation due to the physiological decline of the skin.
Toward an Understanding of the Structural and Mechanistic Aspects of Protein-Protein Interactions in 2-Oxoacid Dehydrogenase Complexes
Authors: Nemeria Natalia S. , Zhang Xu , Leandro Joao , Zhou Jieyu , Yang Luying , Houten Sander M. , Jordan Frank
Published: April 2021

The 2-oxoglutarate dehydrogenase complex (OGDHc) is a key enzyme in the tricarboxylic acid (TCA) cycle and represents one of the major regulators of mitochondrial metabolism through NADH and reactive oxygen species levels. The OGDHc impacts cell metabolic and cell signaling pathways through the coupling of 2-oxoglutarate metabolism to gene transcription related to tumor cell proliferation and aging. DHTKD1 is a gene encoding 2-oxoadipate dehydrogenase (E1a), which functions in the L-lysine degradation pathway. The potentially damaging variants in DHTKD1 have been associated to the (neuro) pathogenesis of several diseases. Evidence was obtained for the formation of a hybrid complex between the OGDHc and E1a, suggesting a potential cross talk between the two metabolic pathways and raising fundamental questions about their assembly. Here we reviewed the recent findings and advances in understanding of protein-protein interactions in OGDHc and 2-oxoadipate dehydrogenase complex (OADHc), an understanding that will create a scaffold to help design approaches to mitigate the effects of diseases associated with dysfunction of the TCA cycle or lysine degradation. A combination of biochemical, biophysical and structural approaches such as chemical cross-linking MS and cryo-EM appears particularly promising to provide vital information for the assembly of 2-oxoacid dehydrogenase complexes, their function and regulation.
Braiding Thermoplastic and Glass Fibers in Composite Dental Post Improves Their Mechanical Compatibility, In Vitro Experiment
Authors: Abdelkader Esraa M. , Nassar Khaled , Melchor Juan , Rus Guillermo
Published: April 2021

Mechanical compatibility with the human dentin is a considerable issue when fabricating dental fiber posts. To this purpose, this study introduces a new method of fabricating compatible dental posts using braiding techniques of thermoplastic fibers (matrix) with glass fibers (reinforcement). Fifty fiber-reinforced composite (FRC) posts of thermoplastic yarns polypropylene (PP) braided with continuous filaments glass fibers (GFs) for reinforcement, varying in fiber volume fraction (FVF), and core types are fabricated and tested. Posts are performed using a braiding machine, and braids are placed in an aluminum mold. The filled mold is playced inside an oven at the melting temperature of the polypropylene to produce the final post’s shape. An ultrasonic test is conducted to measure the shear modulus and Young’s modulus of FRC post specimens by measuring the velocities of both the P-wave and S-wave. In order to ensure the accuracy of the measurements, each sample is measured three times, and then the means and standard deviations of each sample are calculated before analyzing the test results using the means of two steps, namely, clustering and comparing the P and R² values of each cluster, which revealed that FVF, fiber mass, and core type of the specimen had a significant effect on the resulted Young’s and shear modulus. The results indicate that the proposed method can fabricate competitive dental posts with regard to different fabricating variables. The samples show Young’s modulus ranges of from 10.08 GPa to 31.83 GPa. The following tested hypothesis is supported: the braiding technique of thermoplastic fibers with glass fibers will improve the mechanical compatibility of the resulting posts (ex vivo).
Application of Novel Machine Learning Techniques for Predicting the Surface Chloride Concentration in Concrete Containing Waste Material
Authors: Ahmad Ayaz , Farooq Furqan , Ostrowski Krzysztof Adam , Śliwa-Wieczorek Klaudia , Czarnecki Slawomir
Published: April 2021

Structures located on the coast are subjected to the long-term influence of chloride ions, which cause the corrosion of steel reinforcements in concrete elements. This corrosion severely affects the performance of the elements and may shorten the lifespan of an entire structure. Even though experimental activities in laboratories might be a solution, they may also be problematic due to time and costs. Thus, the application of individual machine learning (ML) techniques has been investigated to predict surface chloride concentrations (Cc) in marine structures. For this purpose, the values of Cc in tidal, splash, and submerged zones were collected from an extensive literature survey and incorporated into the article. Gene expression programming (GEP), the decision tree (DT), and an artificial neural network (ANN) were used to predict the surface chloride concentrations, and the most accurate algorithm was then selected. The GEP model was the most accurate when compared to ANN and DT, which was confirmed by the high accuracy level of the K-fold cross-validation and linear correlation coefficient (R2), mean absolute error (MAE), mean square error (MSE), and root mean square error (RMSE) parameters. As is shown in the article, the proposed method is an effective and accurate way to predict the surface chloride concentration without the inconveniences of laboratory tests.
Investigation of the Effect of Mixing Time on the Mechanical Properties of Alkali-Activated Cement Mixed with Fly Ash and Slag
Authors: Kim Taewan , Kang Choonghyun
Published: April 2021

This is an experiment on the effect of mixing time for alkali-activated cement (AAC) using a binder mixed with ground granulated blast furnace slag (slag) and fly ash (FA) in a ratio of 1:1 on the mechanical properties. The mixing method of ASTM C305 was used as the basic mixing method, and the following mixing method was changed. Simply adding the same mixing time and procedure, the difference in the order of mixing slag and FA, and controlling the amount of activator and mixed water were considered. As a result of the experiment, the addition of the same mixing time and procedure, pre-injection of slag, and high-alkali mixed water in which half of the activator and mixing water were mixed showed the highest mechanical properties and a dense pore structure. As a result, the design of a blending method that can promote the activation action of slag rather than FA at room temperature was effective in improving the mechanical properties of AAC. In addition, these blending factors showed a clearer effect as the concentration of the activator increased. Through the results of this experiment, it was shown that high-temperature curing, high fineness of the binder, or even changing the setting of the mixing method without the use of excessive activators can lead to an improvement of mechanical properties.
2D Dynamic Directional Amplification (DDA) in Phononic Metamaterials
Authors: Kalderon Moris , Paradeisiotis Andreas , Antoniadis Ioannis
Published: April 2021

Phononic structures with unit cells exhibiting Bragg scattering and local resonance present unique wave propagation properties at wavelengths well below the regime corresponding to bandgap generation based on spatial periodicity. However, both mechanisms show certain constraints in designing systems with wide bandgaps in the low-frequency range. To face the main practical challenges encountered in such cases, including heavy oscillating masses, a simple dynamic directional amplification (DDA) mechanism is proposed as the base of the phononic lattice. This amplifier is designed to present the same mass and use the same damping element as a reference two-dimensional (2D) phononic metamaterial. Thus, no increase in the structure mass or the viscous damping is needed. The proposed DDA can be realized by imposing kinematic constraints to the structure’s degrees of freedom (DoF), improving inertia and damping on the desired direction of motion. Analysis of the 2D lattice via Bloch’s theory is performed, and the corresponding dispersion relations are derived. The numerical results of an indicative case study show significant improvements and advantages over a conventional phononic structure, such as broader bandgaps and increased damping ratio. Finally, a conceptual design indicates the usage of the concept in potential applications, such as mechanical filters, sound and vibration isolators, and acoustic waveguides.
Effect of Laser Irradiation on Emissivity of Flame-Generated Nanooxides
Authors: De Iuliis Silvana , Dondè Roberto , Altman Igor
Published: April 2021

The application of pyrometry to retrieve particle temperature in particulate-generating flames strictly requires the knowledge of the spectral behavior of emissivity of light-emitting particles. Normally, this spectral behavior is considered time-independent. The current paper challenges this assumption and explains why the emissivity of oxide nanoparticles formed in flame can change with time. The suggested phenomenon is related to transitions of electrons between the valence and conduction energy bands in oxides that are wide-gap dielectrics. The emissivity change is particularly crucial for the interpretation of fast processes occurring during laser-induced experiments. In the present work, we compare the response of titania particles produced by a flame spray to the laser irradiation at two different excitation wavelengths. The difference in the temporal behavior of the corresponding light emission intensities is attributed to the different mechanisms of electron excitation during the laser pulse. Interband transitions that are possible only in the case of the laser photon energy exceeding the titania energy gap led to the increase of the electron density in the conduction band. Relaxation of those electrons back to the valence band is the origin of the observed emissivity drop after the UV laser irradiation.
A Novel Bone Substitute Based on Recombinant Type I Collagen for Reconstruction of Alveolar Cleft
Authors: Ito Masaaki , Toriumi Taku , Hiratsuka Takahiro , Imura Hideto , Akiyama Yasunori , Chimedtseren Ichinnorov , Arai Yoshinori , Yamaguchi Kazuhiro , Azuma Akihiko , Hata Ken-ichiro , Natsume Nagato , Honda Masaki
Published: April 2021

This study aimed to examine the optimal cross-link density of recombinant peptide (RCP) particles, based on human collagen type I, for bone reconstruction in human alveolar cleft. Low- (group 1), medium- (group 2), and high- (group 3) cross-linked RCP particles were prepared by altering the duration of the heat-dependent dehydration reaction. Rat palatine fissures (n = 45), analogous to human congenital bone defects, were examined to evaluate the potential of bone formation by the three different RCP particles. Microcomputed tomography images were obtained to measure bone volume and bone mineral density at 4, 8, 12, and 16 weeks post grafting. Specimens were obtained for histological analysis at 16 weeks after grafting. Additionally, alkaline phosphatase and tartrate acid phosphatase staining were performed to visualize the presence of osteoblasts and osteoclasts. At 16 weeks, bone volume, bone mineral density, and new bone area measurements in group 2 were significantly higher than in any other group. In addition, the number of osteoblasts and osteoclasts on the new bone surface in group 2 was significantly higher than in any other group. Our results demonstrated that medium cross-linking was more suitable for bone formation—and could be useful in human alveolar cleft repairs as well.
Experimental Study on the Influence of Tool Electrode Material on Electrochemical Micromachining of 304 Stainless Steel
Authors: Bian Jianxiao , Ma Baoji , Ai Haihong , Qi Lijun
Published: April 2021

Different cathode materials have different surface chemical components and machining capacities, which may finally result in different machining quality and machining efficiency of workpieces. In this paper, in order to investigate the influence of cathode materials on the electrochemical machining of thin-walled workpiece made of 304 stainless steel, five cylindrical electrodes are used as the target working cathodes of electrochemical machining to conduct experiments and research, including 45# steel, 304 stainless steel, aluminum alloy 6061, brass H62, and tungsten steel YK15. The stray current corrosion, taper, and material removal rate were used as the criteria to evaluate the drilling quality of efficiency of a thin-walled workpiece made of 304 stainless steel. The research results show that from the perspectives of stray current corrosion and taper, aluminum alloy 6061 is an optimal tool cathode, which should be used in the electrochemical machining of thin-walled workpieces made of 304 stainless steel; on the aspect of material removal rate, the 45# steel, 304 stainless steel, and aluminum alloy 6061 present close material removal rates, all of which are higher than that of brass H62 and tungsten steel YK15. Based on comprehensive consideration of both machining quality and machining efficiency, the aluminum alloy 6061 is the best option as the cathode tool in the electrochemical machining of thin-walled workpieces made of 304 stainless steel.
Inactivating SARS-CoV-2 Using 275 nm UV-C LEDs through a Spherical Irradiation Box: Design, Characterization and Validation
Authors: Trivellin Nicola , Buffolo Matteo , Onelia Francesco , Pizzolato Alberto , Barbato Marco , Orlandi Viviana Teresa , Del Vecchio Claudia , Dughiero Fabrizio , Zanoni Enrico , Meneghesso Gaudenzio , Crisanti Andrea , Meneghini Matteo
Published: April 2021

We report on the design, characterization and validation of a spherical irradiation system for inactivating SARS-CoV-2, based on UV-C 275 nm LEDs. The system is designed to maximize irradiation intensity and uniformity and can be used for irradiating a volume of 18 L. To this aim: (i) several commercially available LEDs have been acquired and analyzed; (ii) a complete optical study has been carried out in order to optimize the efficacy of the system; (iii) the resulting prototype has been characterized optically and tested for the inactivation of SARS-CoV-2 for different exposure times, doses and surface types; (iv) the result achieved and the efficacy of the prototype have been compared with similar devices based on different technologies. Results indicate that a 99.9% inactivation can be reached after 1 min of treatment with a dose of 83.1 J/m2.
Composites Based on Hydroxyapatite and Whey Protein Isolate for Applications in Bone Regeneration
Authors: Słota Dagmara , Głąb Magdalena , Tyliszczak Bożena , Douglas Timothy E. L. , Rudnicka Karolina , Miernik Krzysztof , M. Urbaniak Mateusz , Rusek-Wala Paulina , Sobczak-Kupiec Agnieszka
Published: April 2021

Hydroxyapatite (HAp) is a bioactive ceramic with great potential for the regeneration of the skeletal system. However, its mechanical properties, especially its brittleness, limit its application. Therefore, in order to increase its ability to transmit stresses, it can be combined with a polymer phase, which increases its strength without eliminating the important aspect of bioactivity. The presented work focuses on obtaining organic–inorganic hydrogel materials based on whey protein isolate (WPI) reinforced with nano-HAp powder. The proportion of the ceramic phase was in the range of 0–15%. Firstly, a physicochemical analysis of the materials was performed using XRD, FT-IR and SEM. The hydrogel composites were subjected to swelling capacity measurements, potentiometric and conductivity analysis, and in vitro tests in four liquids: distilled water, Ringer’s fluid, artificial saliva, and simulated body fluid (SBF). The incubation results demonstrated the successful formation of new layers of apatite as a result of the interaction with the fluids. Additionally, the influence of the materials on the metabolic activity according to ISO 10993-5:2009 was evaluated by identifying direct contact cytotoxicity towards L-929 mouse fibroblasts, which served as a reference. Moreover, the stimulation of monocytes by hydrogels via the induction of nuclear factor (NF)-κB was investigated. The WPI/HAp composite hydrogels presented in this study therefore show great potential for use as novel bone substitutes.
Mechanical Properties and Durability of Rubberized and Glass Powder Modified Rubberized Concrete for Whitetopping Structures
Authors: Grinys Audrius , Balamurugan Muthaiah , Augonis Algirdas , Ivanauskas Ernestas
Published: April 2021

This paper analyzes concrete fine aggregate (sand) modification by scrap tire rubber particles-fine crumb rubber (FCR) and coarse crumb rubber (CCR) of fraction 0/1 mm. Such rubberized concrete to get better bonding properties were modified by car-boxylated styrene butadiene rubber (SBR) latex and to gain the strength were modified by glass waste. The following tests—slump test, fresh concrete density, fresh concrete air content, compressive strength, flexural strength, fracture energy, freezing-thawing, porosity parameter, and scanning electron microscope—were conducted for rubberized concretes. From experiments, we can see that fresh concrete properties decreased when crumb rubber content has increased. Mostly it is related to crumb rubber (CR) lower specific gravity nature and higher fineness compared with changed fine aggregate-sand. In this research, we obtained a slight loss of compressive strength when CR was used in concrete However, these rubberized concretes with a small amount of rubber provided sufficient compressive strength results (greater than 50 MPa). Due to the pozzolanic reaction, we see that compressive strength results after 56 days in glass powder modified samples increased by 11–13% than 28 days com-pressive strengths, while at the same period control samples increased its compressive strength about 2.5%. Experiments have shown that the flexural strength of rubberized concrete with small amounts of CR increased by 3.4–15.8% compared to control mix, due the fact that rubber is an elastic material and it will absorb high energy and perform positive bending toughness. The test results indicated that CR can intercept the tensile stress in concrete and make the deformation more plastic. Fracturing of such conglomerate concrete is not brittle, there is no abrupt post-peak load drop and gradually continues after the maximum load is exceeded. Such concrete requires much higher fracture energy. It was obtained that FCR particles (lower than A300) will entrap more micropores content than coarse rubbers because due to their high specific area. Freezing-thawing results have confirmed that Kf values can be conveniently used to predict freeze-thaw resistance and durability of concrete. The test has shown that modification of concrete with 10 kg fine rubber waste will lead to similar mechanical and durability properties of concrete as was obtained in control concrete with 2 kg of prefabricated air bubbles.
Unified Model for Laser Doping of Silicon from Precursors
Authors: Hassan Mohamed , Dahlinger Morris , Köhler Jürgen R. , Zapf-Gottwick Renate , Werner Jürgen H.
Published: April 2021

Laser doping of silicon with the help of precursors is well established in photovoltaics. Upon illumination with the constant or pulsed laser beam, the silicon melts and doping atoms from the doping precursor diffuse into the melted silicon. With the proper laser parameters, after resolidification, the silicon is doped without any lattice defects. Depending on laser energy and on the kind of precursor, the precursor either melts or evaporates during the laser process. For high enough laser energies, even parts of the silicon’s surface evaporate. Here, we present a unified model and simulation program, which considers all these cases. We exemplify our model with experiments and simulations of laser doping from a boron oxide precursor layer. In contrast to previous models, we are able to predict not only the width and depth of the patterns on the deformed silicon surface but also the doping profiles over a wide range of laser energies. In addition, we also show that the diffusion of the boron atoms in the molten Si is boosted by a thermally induced convection in the silicon melt: the Gaussian intensity distribution of the laser beam increases the temperature-gradient-induced surface tension gradient, causing the molten Si to circulate by Marangoni convection. Laser pulse energy densities above H > 2.8 J/cm2 lead not only to evaporation of the precursor, but also to a partial evaporation of the molten silicon. Without considering the evaporation of Si, it is not possible to correctly predict the doping profiles for high laser energies. About 50% of the evaporated materials recondense and resolidify on the wafer surface. The recondensed material from each laser pulse forms a dopant source for the subsequent laser pulses.
A Better Approach for Solving a Fuzzy Multiobjective Programming Problem by Level Sets
Authors: Hernández-Jiménez Beatriz , Ruiz-Garzón Gabriel , Beato-Moreno Antonio , Osuna-Gómez Rafaela
Published: April 2021

In this paper, we deal with the resolution of a fuzzy multiobjective programming problem using the level sets optimization. We compare it to other optimization strategies studied until now and we propose an algorithm to identify possible Pareto efficient optimal solutions.
An Intuitive Introduction to Fractional and Rough Volatilities
Authors: Alòs Elisa , León Jorge A.
Published: April 2021

Here, we review some results of fractional volatility models, where the volatility is driven by fractional Brownian motion (fBm). In these models, the future average volatility is not a process adapted to the underlying filtration, and fBm is not a semimartingale in general. So, we cannot use the classical Itô’s calculus to explain how the memory properties of fBm allow us to describe some empirical findings of the implied volatility surface through Hull and White type formulas. Thus, Malliavin calculus provides a natural approach to deal with the implied volatility without assuming any particular structure of the volatility. The aim of this paper is to provides the basic tools of Malliavin calculus for the study of fractional volatility models. That is, we explain how the long and short memory of fBm improves the description of the implied volatility. In particular, we consider in detail a model that combines the long and short memory properties of fBm as an example of the approach introduced in this paper. The theoretical results are tested with numerical experiments.
Parameters Identification of PV Triple-Diode Model Using Improved Generalized Normal Distribution Algorithm
Authors: Abdel-Basset Mohamed , Mohamed Reda , El-Fergany Attia , Abouhawwash Mohamed , Askar S. S.
Published: April 2021

To simulate the behaviors of photovoltaic (PV) systems properly, the best values of the uncertain parameters of the PV models must be identified. Therefore, this paper proposes a novel optimization framework for estimating the parameters of the triple-diode model (TDM) of PV units with different technologies. The proposed methodology is based on the generalized normal distribution optimization (GNDO) with two novel strategies: (i) a premature convergence method (PCM), and (ii) a ranking-based updating method (RUM) to accelerate the convergence by utilizing each individual in the population as much as possible. This improved version of GNDO is called ranking-based generalized normal distribution optimization (RGNDO). RGNDO is experimentally investigated on three commercial PV modules (Kyocera KC200GT, Ultra 85-P and STP 6-120/36) and a solar unit (RTC Si solar cell France), and its extracted parameters are validated based on the measured dataset points extracted at generalized operating conditions. It can be reported here that the best scores of the objective function are equal to 0.750839 mA, 28.212810 mA, 2.417084 mA, and 13.798273 mA for RTC cell, KC200GT, Ultra 85-P, and STP 6-120/36; respectively. Additionally, the principal performance of this methodology is evaluated under various statistical tests and for convergence speed, and is compared with a number of the well-known recent state-of-the-art algorithms. RGNDO is shown to outperform the other algorithms in terms of all the statistical metrics as well as convergence speed. Finally, the performance of the RGNDO is validated in various operating conditions under varied temperatures and sun irradiance levels.
Assessment of Optimization Methods for Aeroacoustic Prediction of Trailing-Edge Interaction Noise in Axisymmetric Jets
Authors: Stirrat Sarah , Afsar Mohammed Z. , Minisci Edmondo
Published: April 2021

Our concern in this paper is in the fine-tuning of the arbitrary parameters within the upstream turbulence structure for the acoustic spectrum of a rapid-distortion theory (RDT)-based model of trailing-edge noise. RDT models are based on an appropriate asymptotic limit of the Linearized Euler Equations and apply when the interaction time of the turbulence with the surface edge discontinuity is small compared to the eddy turnover time. When an arbitrary transversely sheared jet mean flow convects a finite region of nonhomogeneous turbulence, the acoustic spectrum of the pressure field scattered by the trailing-edge depends on (among other things) the upstream turbulence via the Fourier transform of the correlation function, R22 (where subscript 2 refers to a co-ordinate surface normal to the plate). We show that the length and time scale parameters that govern the spatial and temporal de-correlation of R22 can be found using formal optimization methods to avoid any uncertainty in their selection by hand-tuning. We assess various optimization methods that are broadly categorized into an ‘evolutionary’ and ‘non-evolutionary’ paradigm. That is, we optimize the acoustic spectrum using the Multi-Start algorithm, Particle Swarm Optimization and the Multi-Population Adaptive Inflationary Differential Evolution Algorithm. The optimization is based upon different objective functions for the acoustic spectrum and/or turbulence structure. We show that this approach, while resulting in the total modest increase in computation time (on average 2 h), gives excellent prediction over most frequencies (within 2–4 dB) where the trailing-edge noise associated amplification in sound exists.
The Influence of Latent and Chronic Infection on Pathogen Persistence
Authors: O’Neill Xander , White Andy , Clancy Damian , Ruiz-Fons Francisco , Gortázar Christian
Published: April 2021

We extend the classical compartmental frameworks for susceptible-infected-susceptible (SIS) and susceptible-infected-recovered (SIR) systems to include an exposed/latent class or a chronic class of infection. Using a suite of stochastic continuous-time Markov chain models we examine the impact of latent and chronic infection on the mean time to extinction of the infection. Our findings indicate that the mean time to pathogen extinction is increased for infectious diseases which cause exposed/latent infection prior to full infection and that the extinction time is increased further if these exposed individuals are also capable of transmitting the infection. A chronic infection stage can decrease or increase the mean time to pathogen extinction and in particular this depends on whether chronically infected individuals incur disease-induced mortality and whether they are able to transmit the infection. We relate our findings to specific infectious diseases that exhibit latent and chronic infectious stages and argue that infectious diseases with these characteristics may be more difficult to manage and control.