bluuebunny/crossref_metadata_2025 huggingface dataset:
Multi-Walled Carbon Nanotubes Can Promote Brassica napus L. and Arabidopsis thaliana L. Root Hair Development through Nitric Oxide and Ethylene Pathways
Authors: Zhao Gan , Zhao Yingying , Lou Wang , Abdalmegeed Dyaaaldin , Guan Rongzhan , Shen Wenbiao
Published: November 2020

Here, we report that multi-walled carbon nanotubes (MWCNTs) can promote plant root hair growth in the species analyzed in this study; however, low and excessive concentrations of MWCNTs had no significant effect or even an inhibiting influence. Further results show that MWCNTs can enter rapeseed root cells. Meanwhile, nitrate reductase (NR)-dependent nitric oxide (NO) and ethylene syntheses, as well as root hair formation, were significantly stimulated by MWCNTs. Transcription of root hair growth-related genes were also modulated. The above responses were sensitive to the removal of endogenous NO or ethylene with a scavenger of NO or NO/ethylene synthesis inhibitors. Pharmacological and molecular evidence suggested that ethylene might act downstream of NR-dependent NO in MWCNTs-induced root hair morphogenesis. Genetic evidence in Arabidopsis further revealed that MWCNTs-triggered root hair growth was abolished in ethylene-insensitive mutants ein2-5 and ein3-1, and NR mutant nia1/2, but not in noa1 mutant. Further data placed NO synthesis linearly before ethylene production in root hair development triggered by MWCNTs. The above findings thus provide some insights into the molecular mechanism underlying MWCNTs control of root hair morphogenesis.
Effectiveness in Block by Dexmedetomidine of Hyperpolarization-Activated Cation Current, Independent of Its Agonistic Effect on α2-Adrenergic Receptors
Authors: Lu Te-Ling , Lu Te-Jung , Wu Sheng-Nan
Published: November 2020

Dexmedetomidine (DEX), a highly selective agonist of α2-adrenergic receptors, has been tailored for sedation without risk of respiratory depression. Our hypothesis is that DEX produces any direct perturbations on ionic currents (e.g., hyperpolarization-activated cation current, Ih). In this study, addition of DEX to pituitary GH3 cells caused a time- and concentration-dependent reduction in the amplitude of Ih with an IC50 value of 1.21 μM and a KD value of 1.97 μM. A hyperpolarizing shift in the activation curve of Ih by 10 mV was observed in the presence of DEX. The voltage-dependent hysteresis of Ih elicited by long-lasting triangular ramp pulse was also dose-dependently reduced during its presence. In continued presence of DEX (1 μM), further addition of OXAL (10 μM) or replacement with high K+ could reverse DEX-mediated inhibition of Ih, while subsequent addition of yohimbine (10 μM) did not attenuate the inhibitory effect on Ih amplitude. The addition of 3 μM DEX mildly suppressed the amplitude of erg-mediated K+ current. Under current-clamp potential recordings, the exposure to DEX could diminish the firing frequency of spontaneous action potentials. In pheochromocytoma PC12 cells, DEX was effective at suppressing Ih together with a slowing in activation time course of the current. Taken together, findings from this study strongly suggest that during cell exposure to DEX used at clinically relevant concentrations, the DEX-mediated block of Ih appears to be direct and would particularly be one of the ionic mechanisms underlying reduced membrane excitability in the in vivo endocrine or neuroendocrine cells.
Mouse Models of Sjögren’s Syndrome with Ocular Surface Disease
Authors: Masli Sharmila , Dartt Darlene A.
Published: November 2020

Sjögren’s syndrome (SS) is a systemic rheumatic disease that predominantly affects salivary and lacrimal glands resulting in oral and ocular dryness, respectively, referred to as sicca symptoms. The clinical presentation of ocular dryness includes keratoconjunctivitis sicca (KCS), resulting from the inflammatory damage to the ocular surface tissues of cornea and conjunctiva. The diagnostic evaluation of KCS is a critical component of the classification criteria used by clinicians worldwide to confirm SS diagnosis. Therapeutic management of SS requires both topical and systemic treatments. Several mouse models of SS have contributed to our current understanding of immunopathologic mechanisms underlying the disease. This information also helps develop novel therapeutic interventions. Although these models address glandular aspects of SS pathology, their impact on ocular surface tissues is addressed only in a few models such as thrombospondin (TSP)-1 deficient, C57BL/6.NOD.Aec1Aec2, NOD.H2b, NOD.Aire KO, and IL-2Rα (CD25) KO mice. While corneal and/or conjunctival damage is reported in most of these models, the characteristic SS specific autoantibodies are only reported in the TSP-1 deficient mouse model, which is also validated as a preclinical model. This review summarizes valuable insights provided by investigations on the ocular spectrum of the SS pathology in these models.
Syringic Acid Alleviates Cesium-Induced Growth Defect in Arabidopsis
Authors: Adams Eri , Miyazaki Takae , Moon Ju Yeon , Sawada Yuji , Sato Muneo , Toyooka Kiminori , Hirai Masami Yokota , Shin Ryoung
Published: November 2020

Syringic acid, a phenolic compound, serves a variety of beneficial functions in cells. Syringic acid increases in plants in response to cesium, and exogenous application of syringic acid resulted in a significant attenuation of cesium-induced growth defects in Arabidopsis. In addition, cesium or syringic acid application to plants also resulted in increased lignin deposition in interfascicular fibers. To better understand the role of lignin and syringic acid in attenuating cesium-induced growth defects, two mutants for Arabidopsis REDUCED EPIDERMAL FLUORESCENE 4 (REF4) and fourteen laccase mutants, some of which have lower levels of lignin, were evaluated for their response to cesium. These mutants responded differently to cesium stress, compared to control plants, and the application of syringic acid alleviated cesium-induced growth defects in the laccase mutants but not in the ref4 mutants. These findings imply that lignin plays a role in cesium signaling but the attenuation of cesium stress defects by syringic acid is mediated by regulatory components of lignin biosynthesis and not lignin biosynthesis itself. In contrast, syringic acid did not alleviate any low potassium-induced growth defects. Collectively, our findings provide the first established link between lignin and cesium stress via syringic acid in plants.
Functional Comparison of Blood-Derived Human Neural Progenitor Cells
Authors: Szabó Eszter , Juhász Flóra , Hathy Edit , Reé Dóra , Homolya László , Erdei Zsuzsa , Réthelyi János M. , Apáti Ágota
Published: November 2020

Induced pluripotent stem cell (iPSC)-derived neural progenitor cells (NPCs) are promising tools to model complex neurological or psychiatric diseases, including schizophrenia. Multiple studies have compared patient-derived and healthy control NPCs derived from iPSCs in order to investigate cellular phenotypes of this disease, although the establishment, stabilization, and directed differentiation of iPSC lines are rather expensive and time-demanding. However, interrupted reprogramming by omitting the stabilization of iPSCs may allow for the generation of a plastic stage of the cells and thus provide a shortcut to derive NPSCs directly from tissue samples. Here, we demonstrate a method to generate shortcut NPCs (sNPCs) from blood mononuclear cells and present a detailed comparison of these sNPCs with NPCs obtained from the same blood samples through stable iPSC clones and a subsequent neural differentiation (classical NPCs—cNPCs). Peripheral blood cells were obtained from a schizophrenia patient and his two healthy parents (a case–parent trio), while a further umbilical cord blood sample was obtained from the cord of a healthy new-born. The expression of stage-specific markers in sNPCs and cNPCs were compared both at the protein and RNA levels. We also performed functional tests to investigate Wnt and glutamate signaling and the oxidative stress, as these pathways have been suggested to play important roles in the pathophysiology of schizophrenia. We found similar responses in the two types of NPCs, suggesting that the shortcut procedure provides sNPCs, allowing an efficient screening of disease-related phenotypes.
Role of Epithelial–Mesenchymal Plasticity in Pseudomyxoma Peritonei: Implications for Locoregional Treatments
Authors: Calabrò Maria Luisa , Lazzari Nayana , Rigotto Giulia , Tonello Marco , Sommariva Antonio
Published: November 2020

The mechanisms by which neoplastic cells disseminate from the primary tumor to metastatic sites, so-called metastatic organotropism, remain poorly understood. Epithelial–mesenchymal transition (EMT) plays a role in cancer development and progression by converting static epithelial cells into the migratory and microenvironment-interacting mesenchymal cells, and by the modulation of chemoresistance and stemness of tumor cells. Several findings highlight that pathways involved in EMT and its reverse process (mesenchymal–epithelial transition, MET), now collectively called epithelial–mesenchymal plasticity (EMP), play a role in peritoneal metastases. So far, the relevance of factors linked to EMP in a unique peritoneal malignancy such as pseudomyxoma peritonei (PMP) has not been fully elucidated. In this review, we focus on the role of epithelial–mesenchymal dynamics in the metastatic process involving mucinous neoplastic dissemination in the peritoneum. In particular, we discuss the role of expression profiles and phenotypic transitions found in PMP in light of the recent concept of EMP. A better understanding of EMP-associated mechanisms driving peritoneal metastasis will help to provide a more targeted approach for PMP patients selected for locoregional interventions involving cytoreductive surgery and hyperthermic intraperitoneal chemotherapy.
Hospitalization and Socio-Health Care for Dementia in Spain
Authors: Llanes-Álvarez Carlos , llano Jesús M. Andrés-de , Álvarez-Navares Ana I. , Roncero Carlos , Pastor-Hidalgo M. Teresa , Garmendia-Leiza José R. , Andrés-Alberola Irene , Franco-Martín Manuel A.
Published: November 2020

Dementias are brain diseases that affect long-term cognitive and behavioral functions and cause a decrease in the ability to think and remember that is severe enough to disturb daily functioning. In Spain, the number of people suffering from dementia is rising due to population ageing. Reducing admissions, many of them avoidable, would be advantageous for patients and care-providers. Understanding the correlation of admission of people with dementia and its trends in hospitalization would help us to understand the factors leading to admission. We conducted a cross-sectional study of the hospital discharge database of Castilla y León from 2005 to 2015, selecting hospitalizations for dementia. Trends in hospitalizations by year and age quartiles were studied by joinpoint regression analysis. 2807 out of 2,717,192 total hospitalizations (0.10%) were due to dementias; the main groups were degenerative dementia (1907) followed by vascular dementia (607). Dementias are not a major cause of hospitalization, but the average stay and cost are high, and many of them seem avoidable. Decreasing trends were detected in hospitalization rates for all dementias except for the group of mild cognitive impairment, which grew. An increasing–decreasing joinpoint detected in 2007 for vascular dementia and the general downward hospitalization trends for most dementias suggest that socio-health measures established since 2007 in Spain might play a key role in reducing hospitalizations.
Did the Brain and Oral Microbiota Talk to Each Other? A Review of the Literature
Authors: Maitre Yoann , Micheneau Pierre , Delpierre Alexis , Mahalli Rachid , Guerin Marie , Amador Gilles , Denis Frederic
Published: November 2020

This systematic review aims to investigate the role of the oral microbiome in the pathophysiology of mental health disorders and to appraise the methodological quality of research of the oral–brain axis which is a growing interest area. The PRISMA guideline was adopted, to carry out an electronic search through the MEDLINE database, to identify studies that have explored the role of the oral microbiome in the pathophysiology of mental health disorders published from 2000 up to June 2020. The search resulted in 140 records; after exclusions, a total of 22 papers were included in the present review. In accordance with the role of the oral microbiome in the pathophysiology of mental disorders, four mental disorders were identified: Alzheimer’s disease, dementia, and cognitive disorders; autism spectrum disorder; Down’s syndrome and mental retardation; and Bipolar disorders. Studies argue for correlations between oral microbiota and Alzheimer’s disease, autism spectrum disorders, Down’s syndrome, and bipolar disorders. This field is still under-studied, and studies are needed to clarify the biological links and interconnections between the oral microbiota and the pathophysiology of all mental health disorders. Researchers should focus their efforts to develop research on the oral–brain axis in the future.
A Proposed Algorithm for Endoscopic Ultrasound-Guided Rendezvous Technique in Failed Biliary Cannulation
Authors: Matsubara Saburo , Nakagawa Keito , Suda Kentaro , Otsuka Takeshi , Isayama Hiroyuki , Nakai Yousuke , Oka Masashi , Nagoshi Sumiko
Published: November 2020

Background: The selection of an approach route in endoscopic ultrasound-guided rendezvous (EUS-RV) for failed biliary cannulation is complicated. We proposed an algorithm for EUS-RV. Methods: We retrospectively evaluated consecutive EUS-RV cases between April 2017 and July 2020. Puncturing the distal extrahepatic bile duct (EHBD) from the duodenal second part (D2) (DEHBD/D2 route) was attempted first. If necessary, puncturing the proximal EHBD from the duodenal bulb (D1) (PEHBD/D1 route), puncturing the left intrahepatic bile duct (IHBD) from the stomach (LIHBD/S route), or puncturing the right IHBD from the D1 (RIHBD/D1 route) were attempted in this order. Results: A total of 16 patients were included. The DEHBD/D2 route was used in 10 (62.5%) patients. The PEHBD/D1 route was attempted in five (31.3%) patients, and the biliary puncture failed in one patient in whom the RIHBD/D1 route was used because of tumor invasion to the left hepatic lobe. The LIHBD/S route was applied in one (6.3%) patient. Successful biliary cannulation was achieved in all patients eventually. The time from the puncture to the guidewire placement in the DEHBD/D2 route (3.5 min) was shorter than that in other methods (14.0 min) (p = 0.014). Adverse events occurred in one (6.3%) patient with moderate pancreatitis. Conclusions: The proposed algorithm might be useful for the selection of an appropriate approach route in EUS-RV.
Role of Surgical Intervention in Unresectable Non-Small Cell Lung Cancer
Authors: Suzuki Shigeki , Goto Taichiro
Published: November 2020

With the development of systemic treatments with high response rates, including tyrosine kinase inhibitors and immune checkpoint inhibitors, some patients with unresectable lung cancer now have a chance to undergo radical resection after primary treatment. Although there is no general consensus regarding the definition of “unresectable” in lung cancer, the term “resectable” refers to technically resectable and indicates that resection can provide a favorable prognosis to some extent. Unresectable lung cancer is typically represented by stage III and IV disease. Stage III lung cancer is a heterogeneous disease, and in some patients with technically resectable non-small cell lung cancer (NSCLC), multimodality treatments, including induction chemoradiotherapy followed by surgery, are the treatments of choice. The representative surgical intervention for unresectable stage III/IV NSCLC is salvage surgery, which refers to surgical treatment for local residual/recurrent lesions after definitive non-surgical treatment. Surgical intervention is also used for an oligometastatic stage IV NSCLC. In this review, we highlight the role of surgical intervention in patients with unresectable NSCLC, for whom an initial complete resection is technically difficult. We further describe the history of and new findings on salvage surgery for unresectable NSCLC and surgery for oligometastatic NSCLC.
Could Periodontal Disease through Periopathogen Fusobacterium nucleatum Be an Aggravating Factor for Gastric Cancer?
Authors: Șurlin Petra , Nicolae Flavia Mirela , Șurlin Valeriu Marin , Pătrașcu Ștefan , Ungureanu Bogdan Silviu , Didilescu Andreea Cristiana , Gheonea Dan Ionuț
Published: November 2020

Periodontal disease affects the supporting tissues of the teeth, being a chronic inflammatory disease caused by specific microorganisms from subgingival biofilm. Fusobacterium nucleatum is a Gram-negative anaerobic bacterium that acts as a periodontal pathogen, being an important factor in linking Gram-positive and Gram-negative bacteria in the periodontal biofilm, but its involvement in systemic diseases has also been found. Several studies regarding the implication of Fusobacterium nucleatum in gastro-enterological cancers have been conducted. The present review aims to update and systematize the latest information about Fusobacterium nucleatum in order to evaluate the possibility of an association between periodontal disease and the evolution of gastroenterological cancers through the action of Fusobacterium nucleatum, highlighting gastric cancer. This would motivate future research on the negative influence of periodontal pathology on the evolution of gastric cancer in patients suffering from both pathologies.
Effect of Fisheries Subsidies Negotiations on Fish Production and Interest Rate
Authors: Kumar Radika , Kumar Ronald Ravinesh , Stauvermann Peter Josef , Arora Pallavi
Published: November 2020

We analyze the effect of fisheries subsidy negotiations on financial markets and aggregate demand in developed and developing countries. We examine the plausible scenarios that are likely to emerge in the event of elimination or reduction of subsidies, and the subsequent effect on the financial markets and the fish production. We use the Keynesian macroeconomic static framework, which is based on an extended well-known investment-savings (IS) and liquidity preference–money supply (LM) model for analysis. Our analysis shows that the impact of a reduction in fisheries subsidies would reduce the exploitation of fish and marine resources in developing countries, thus leading to a general increase in fish prices and quantity stabilizing at lower levels. We also find that this effect would transfer to financial markets, leading to a decline in interest rates for fish exporting developing countries, but interest rates tend to stabilize at higher levels for fish importing developed countries.
Early Warning Signs of Financial Market Turmoils
Authors: Bertschinger Nils , Pfante Oliver
Published: November 2020

Volatility clustering and fat tails are prominently observed in financial markets. Here, we analyze the underlying mechanisms of three agent-based models explaining these stylized facts in terms of market instabilities and compare them on empirical grounds. To this end, we first develop a general framework for detecting tail events in stock markets. In particular, we introduce Hawkes processes to automatically identify and date onsets of market turmoils which result in increased volatility. Second, we introduce three different indicators to predict those onsets. Each of the three indicators is derived from and tailored to one of the models, namely quantifying information content, critical slowing down or market risk perception. Finally, we apply our indicators to simulated and real market data. We find that all indicators reliably predict market events on simulated data and clearly distinguish the different models. In contrast, a systematic comparison on the stocks of the Forbes 500 companies shows a markedly lower performance. Overall, predicting the onset of market turmoils appears difficult, yet, over very short time horizons high or rising volatility exhibits some predictive power.
Face Recognition in an Unconstrained and Real-Time Environment Using Novel BMC-LBPH Methods Incorporates with DJI Vision Sensor
Authors: Ahsan Md Manjurul , Li Yueqing , Zhang Jing , Ahad Md Tanvir , Yazdan Munshi Md. Shafwat
Published: November 2020

Face recognition (FR) in an unconstrained environment, such as low light, illumination variations, and bad weather is very challenging and still needs intensive further study. Previously, numerous experiments on FR in an unconstrained environment have been assessed using Eigenface, Fisherface, and Local binary pattern histogram (LBPH) algorithms. The result indicates that LBPH FR is the optimal one compared to others due to its robustness in various lighting conditions. However, no specific experiment has been conducted to identify the best setting of four parameters of LBPH, radius, neighbors, grid, and the threshold value, for FR techniques in terms of accuracy and computation time. Additionally, the overall performance of LBPH in the unconstrained environments are usually underestimated. Therefore, in this work, an in-depth experiment is carried out to evaluate the four LBPH parameters using two face datasets: Lamar University data base (LUDB) and 5_celebrity dataset, and a novel Bilateral Median Convolution-Local binary pattern histogram (BMC-LBPH) method was proposed and examined in real-time in rainy weather using an unmanned aerial vehicle (UAV) incorporates with 4 vision sensors. The experimental results showed that the proposed BMC-LBPH FR techniques outperformed the traditional LBPH methods by achieving the accuracy of 65%, 98%, and 78% in 5_celebrity dataset, LU dataset, and rainy weather, respectively. Ultimately, the proposed method provides a promising solution for facial recognition using UAV.
Interrogating the Role and Value of Cultural Expertise in Law
Authors: Campbell John
Published: November 2020

It is common for litigation to draw upon expert evidence to assist a judge to arrive at a balanced decision. This paper examines the role of one type of expert evidence submitted to courts, namely cultural expertise (CE), which provides information on socio-cultural issues such as kinship, family, marriage, customs, language, religion, witchcraft and so on. This type of evidence is primarily the result of qualitative, ethnographic research. I begin by examining the views of experts who have provided CE to courts/mediators; I then look at how judges view and make use of CE, and finally I examine lawyers’ views on CE. To address gaps in published research, I interviewed British barristers to understand how they make use of experts in the cases they litigate. Finally, I have surveyed legal decisions made by all British appellate courts to arrive at an approximate idea of the extent to which CE has been submitted in English and Welsh courts. I conclude that the extent to which CE—and other types of socio-legal evidence—is submitted varies considerably depending upon the legal/evidentiary procedures followed in different jurisdictions and in different countries.
Calcifying Bacteria Flexibility in Induction of CaCO3 Mineralization
Authors: Golovkina Darya A. , Zhurishkina Elena V. , Ivanova Lyubov A. , Baranchikov Alexander E. , Sokolov Alexey Y. , Bobrov Kirill S. , Masharsky Alexey E. , Tsvigun Natalia V. , Kopitsa Gennady P. , Kulminskaya Anna A.
Published: November 2020

Microbially induced CaCO3 precipitation (MICP) is considered as an alternative green technology for cement self-healing and a basis for the development of new biomaterials. However, some issues about the role of bacteria in the induction of biogenic CaCO3 crystal nucleation, growth and aggregation are still debatable. Our aims were to screen for ureolytic calcifying microorganisms and analyze their MICP abilities during their growth in urea-supplemented and urea-deficient media. Nine candidates showed a high level of urease specific activity, and a sharp increase in the urea-containing medium pH resulted in efficient CaCO3 biomineralization. In the urea-deficient medium, all ureolytic bacteria also induced CaCO3 precipitation although at lower pH values. Five strains (B. licheniformis DSMZ 8782, B. cereus 4b, S. epidermidis 4a, M. luteus BS52, M. luteus 6) were found to completely repair micro-cracks in the cement samples. Detailed studies of the most promising strain B. licheniformis DSMZ 8782 revealed a slower rate of the polymorph transformation in the urea-deficient medium than in urea-containing one. We suppose that a ureolytic microorganism retains its ability to induce CaCO3 biomineralization regardless the origin of carbonate ions in a cell environment by switching between mechanisms of urea-degradation and metabolism of calcium organic salts.
Application of the Numerical Model to Design the Geometry of a Unit Tool in the Innovative RTH Hydroforming Technology
Authors: Sadłowska Hanna , Kochański Andrzej , Czapla Magdalena
Published: November 2020

The article presents a newly patented rapid tube hydroforming (RTH) manufacturing method, perfectly suited to single-piece production. The RTH technology significantly complements the scope of hydroforming processes. Due to the unusual granular material of the die tool, in particular moulding sand or mass, the process design requires the use of numerical modelling calculations. This is related to the complexity and the synergistic effect of process parameters on the final shape of the product. The work presents the results of numerical modelling studies of the process, including the behaviour of the die material and the material of the hydroformed profile. The numerical calculations were performed for a wide range of parameters, and can be used in various applications. The significant properties of moulding material used for the RTH tests were determined and one was chosen to build the die in RTH experiments. The results of the numerical modelling were compared with the results of the experiments, which proved their high compatibility. The final conclusions of the analyses indicate that the RTH technology has many possibilities that are worth further development and research.
Enhancement of Interface between Lignocellulosic Fibers and Polypropylene Matrix via the Structure Alteration of Lignin at Elevated Temperatures
Authors: Dong Zhen , Li Na , Dong Aixue , Ma Bomou , Yu Chongwen , Chu Teye , Liu Qixia
Published: November 2020

This paper investigated the feasibility of enhancing the interface between lignocellulosic fibers and a polypropylene matrix via structure alteration of lignin at elevated temperatures. Alkali treatment can remove gum substances from lignocellulose fibers effectively at elevated temperatures but easily causes damages to fiber strength. In previous studies on directional delignification of lignocellulosic fibers, loss of fiber strength is avoided but condensation and degradation of lignin are accelerated. So far, few reports have been available on the effect of lignin structures on the interface between fibers and a matrix. In this study, jute fibers with different lignin structures are produced at 100 and 130 °C for reinforcing a polypropylene matrix. The interface between the fibers and matrix is analyzed. The result shows that decrease in aliphatic hydroxyl concentration by 9.5% at 130 °C from 3 to 5 h contributes to a 14.2% decrease in the surface energy of jute fibers. Meanwhile, the polydispersity index of lignin decreases from 1.21 to 1.15. Centralized distribution of lignin molecule-weight and reduction in fiber surface energy improves the interface between the fibers and matrix, which manifests as a 30.8% increase in the impact strength of the composites. Similar improvement is not observed in the composites reinforced with jute fibers at 100 °C, due to the absence of lignin-structure changes. This paper provides a new strategy to improve the interface between lignocellulose fibers and a hydrophobic matrix.
Effect of Basalt Powder Surface Treatments on Mechanical and Processing Properties of Polylactide-Based Composites
Authors: Barczewski Mateusz , Mysiukiewicz Olga , Lewandowski Krzysztof , Nowak Daniel , Matykiewicz Danuta , Andrzejewski Jacek , Skórczewska Katarzyna , Piasecki Adam
Published: November 2020

Legislative restrictions and the needs of consumers have created a demand for sustainable materials. Polylactide (PLA) is a biodegradable polyester with advantageous mechanical properties, however, due to its low crystallization rate, it also has low thermomechanical stability. Its range of application temperatures can be widened using nucleating agents and fillers including basalt powder (BP), a waste product from the mining industry. This study analyzed the possibility of enhancing the properties of a PLA-BP composite by chemically treating the filler. Basalt powder was subjected to silanization with 3-aminopropyltriethoxysilane or γ-glycidoxypropyltrimethoxysilane and mixed with PLA at 5–20 wt%. The nucleating effect of a potassium salt of 3,5-bis(methoxycarbonyl) (LAK-301) in the silanized composite was also evaluated. The properties of the materials with silanized BP were compared with the unmodified basalt powder. The miscibility of the filler and the polymer was assessed by oscillatory rheometry. The structure of the composites was studied using scanning electron microscopy and their thermomechanical properties were analyzed using dynamic mechanical thermal analysis. Mechanical properties such as tensile strength, hardness and impact strength, and heat deflection temperature of the materials were also determined. It was concluded that BP-filled nucleated PLA composites presented satisfactory thermomechanical stability without silanization, but chemical treatment could improve the matrix–filler interactions.
AI-Optimized Technological Aspects of the Material Used in 3D Printing Processes for Selected Medical Applications
Authors: Rojek Izabela , Mikołajewski Dariusz , Dostatni Ewa , Macko Marek
Published: November 2020

While the intensity, complexity, and specificity of robotic exercise may be supported by patient-tailored three-dimensional (3D)-printed solutions, their performance can still be compromised by non-optimal combinations of technological parameters and material features. The main focus of this paper was the computational optimization of the 3D-printing process in terms of features and material selection in order to achieve the maximum tensile force of a hand exoskeleton component, based on artificial neural network (ANN) optimization supported by genetic algorithms (GA). The creation and 3D-printing of the selected component was achieved using Cura 0.1.5 software and 3D-printed using fused filament fabrication (FFF) technology. To optimize the material and process parameters we compared ten selected parameters of the two distinct printing materials (polylactic acid (PLA), PLA+) using ANN supported by GA built and trained in the MATLAB environment. To determine the maximum tensile force of the exoskeleton, samples were tested using an INSTRON 5966 universal testing machine. While the balance between the technical requirements and user safety constraints requires further analysis, the PLA-based 3D-printing parameters have been optimized. Additive manufacturing may support the successful printing of usable/functional exoskeleton components. The network indicated which material should be selected: Namely PLA+. AI-based optimization may play a key role in increasing the performance and safety of the final product and supporting constraint satisfaction in patient-tailored solutions.
Multi-Dimensional Mathematical Wear Models of Vibration Generated by Rolling Ball Bearings Made of AISI 52100 Bearing Steel
Authors: Zmarzły Paweł
Published: November 2020

The paper features the development of multi-dimensional mathematical models used for evaluating the impact of selected factors on the vibration generated by 6304ZZ type rolling ball bearings from three manufacturers in the aspect of the wear process. The bearings were manufactured of AISI 52100 bearing steel. The analyzed factors included the inner and outer raceways’ roundness and waviness deviations, radial clearance and the total curvature ratio. The models were developed for vibration recorded in three frequency ranges: 50–300 Hz, 300–1800 Hz and 1800–10,000 Hz. The paper includes a specification of the principles of operation of innovative measuring systems intended for testing bearing vibration, raceway geometries and radial clearance. Furthermore, it features a specification of particular stages of the multi-dimensional mathematical models’ development and verification. Testing with the purpose of statistical evaluation of the analyzed factors is also presented. The test results and mathematical models indicate that the inner raceway’s waviness deviation had a dominant impact on the vibration examined in all frequencies. The roundness and waviness deviation of bearing raceways made of AISI 52100 steel propagates the bearing wear process.
Preparation of Continuous Alumina Fiber with Nano Grains by the Addition of Iron Sol
Authors: Liu Luqun , Wang Juan , Ma Yunzhu , Liu Wensheng , Yao Shuwei
Published: November 2020

Continuous alumina fiber exhibits excellent mechanical properties owing to its dense microstructure with fine grains. In this study, alumina fiber was prepared by the sol–gel method using iron sol as a nucleating agent. It was proposed that the α-Al2O3 grain size be adjusted based on the modification of colloidal particle size. The effect of holding temperature and reaction material ratio on the iron colloidal particle size was studied. The microstructure of alumina fiber was characterized by scanning electron microscopy (SEM). The experiment results indicated that iron colloidal particle size increases with the holding temperature and the NH4HCO3/Fe(NO3)3·9H2O ratio. The alumina fiber with uniform nano α-Al2O3 grains was obtained by calcination at 1400 °C for 5 min. The mean grain size tends to rise with the mean colloidal particle size. Using the iron sol as a nucleating agent, the fiber with a mean grain size of 22.5 nm could be formed. The tensile strength of fibers increased with the decrease of grain size.
Orientation Dependence of Cathodoluminescence and Photoluminescence Spectroscopy of Defects in Chemical-Vapor-Deposited Diamond Microcrystal
Authors: Fabisiak Kazimierz , Łoś Szymon , Paprocki Kazimierz , Szybowicz Mirosław , Winiecki Janusz , Dychalska Anna
Published: November 2020

Point defects, impurities, and defect–impurity complexes in diamond microcrystals were studied with the cathodoluminescence (CL) spectroscopy in the scanning electron microscope, photoluminescence (PL), and Raman spectroscopy (RS). Such defects can influence the directions that microcrystals are grown. Micro-diamonds were obtained by a hot-filament chemical vapor deposition (HF CVD) technique from the methane–hydrogen gas mixture. The CL spectra of diamond microcrystals taken from (100) and (111) crystallographic planes were compared to the CL spectrum of a (100) oriented Element Six diamond monocrystal. The following color centers were identified: 2.52, 2.156, 2.055 eV attributed to a nitrogen–vacancy complex and a violet-emitting center (A-band) observed at 2.82 eV associated with dislocation line defects, whose atomic structure is still under discussion. The Raman studies showed that the planes (111) are more defective in comparison to (100) planes. What is reflected in the CL spectra as (111) shows a strong band in the UV region (2.815 eV) which is not observed in the case of the (100) plane.
The Effect of Ni Interlayer on the Hot-Rolled and Quenched Stainless Steel Clad Plate
Authors: Lin Zengmeng , Wang Shuai , He Jun , Liu Baoxi , Chen Cuixin , Feng Jianhang , Zhang Xin , Fang Wei , Yin Fuxing
Published: November 2020

The vacuum hot-rolled SUS314/Q235 stainless steel clad plate has many drawbacks including serious interface alloy element diffusion, stainless steel cladding’s sensitization, and carbon steel substrate’s low strength. In this study, the comprehensive properties were systematically adjusted by changing the thickness of the Ni interlayer (0, 100, 200 μm) and the quenching temperature (1000~1150 °C). The results showed that the Ni interlayer can obviously hinder the diffusion of carbon element, so as to achieve the purpose of eliminating the decarburized layer and reducing the carbon content of the carburized layer. Meanwhile, the perfect metallurgical bonding between the substrate and cladding can be obtained, effectively improving the stainless steel clad plate’s tensile shear strength and comprehensive mechanical properties, and significantly reduce the brittleness of the carburized layer. As the quenching temperature increases, the grains coarsening of carbon steel and stainless steel became more and more serious, and the sensitization phenomenon and the thickness of the carburized layer are gradually decreased. The stainless steel clad plate (Ni layer thickness of 100 μm) quenched at 1050 °C had the best comprehensive mechanical properties. Herein, the interface shear strength, tensile strength and the fracture elongation reached 360.5 MPa, 867 MPa and 16.10%, respectively, achieving strengthening and toughening aim. This is attributed to the disappearance of the sensitization phenomenon, the grain refinement and the lower interface residual stress.
Synthesis, Cytotoxic Activity Evaluation and Quantitative Structure-ActivityAnalysis of Substituted 5,8-Dihydroxy-1,4-naphthoquinones and Their O- and S-Glycoside Derivatives Tested against Neuro-2a Cancer Cells
Authors: Polonik Sergey , Likhatskaya Galina , Sabutski Yuri , Pelageev Dmitry , Denisenko Vladimir , Pislyagin Evgeny , Chingizova Ekaterina , Menchinskaya Ekaterina , Aminin Dmitry
Published: November 2020

Based on 6,7-substituted 2,5,8-trihydroxy-1,4-naphtoquinones (1,4-NQs) derived from sea urchins, five new acetyl-O-glucosides of NQs were prepared. A new method of conjugation of per-O-acetylated 1-mercaptosaccharides with 2-hydroxy-1,4-NQs through a methylene spacer was developed. Methylation of 2-hydroxy group of quinone core of acetylthiomethylglycosides by diazomethane and deacetylation of sugar moiety led to 28 new thiomethylglycosidesof 2-hydroxy- and 2-methoxy-1,4-NQs. The cytotoxic activity of starting 1,4-NQs (13 compounds) and their O- and S-glycoside derivatives (37 compounds) was determined by the MTT method against Neuro-2a mouse neuroblastoma cells. Cytotoxic compounds with EC50 = 2.7–87.0 μM and nontoxic compounds with EC50 > 100 μM were found. Acetylated O- and S-glycosides 1,4-NQs were the most potent, with EC50 = 2.7–16.4 μM. Methylation of the 2-OH group innaphthoquinone core led to a sharp increase in the cytotoxic activity of acetylated thioglycosidesof NQs, which was partially retained for their deacetylated derivatives. Thiomethylglycosides of 2-hydroxy-1,4-NQs with OH and MeO groups in quinone core at positions 6 and 7, resprectively formed a nontoxic set of compounds with EC50 > 100 μM. A quantitative structure-activity relationship (QSAR) model of cytotoxic activity of 22 1,4-NQ derivatives was constructed and tested. Descriptors related to the cytotoxic activity of new 1,4-NQ derivatives were determined. The QSAR model is good at predicting the activity of 1,4-NQ derivatives which are unused for QSAR models and nontoxic derivatives.
A New Bioassay Platform Design for the Discovery of Small Molecules with Anticancer Immunotherapeutic Activity
Authors: Gallo Carmela , Barra Giusi , Saponaro Marisa , Manzo Emiliano , Fioretto Laura , Ziaco Marcello , Nuzzo Genoveffa , d’Ippolito Giuliana , De Palma Raffaele , Fontana Angelo
Published: November 2020

Immunotherapy takes advantage of the immune system to prevent, control, and eliminate neoplastic cells. The research in the field has already led to major breakthroughs to treat cancer. In this work, we describe a platform that integrates in vitro bioassays to test the immune response and direct antitumor effects for the preclinical discovery of anticancer candidates. The platform relies on the use of dendritic cells that are professional antigen-presenting cells (APC) able to activate T cells and trigger a primary adaptive immune response. The experimental procedure is based on two phenotypic assays for the selection of chemical leads by both a panel of nine tumor cell lines and growth factor-dependent immature mouse dendritic cells (D1). The positive hits are then validated by a secondary test on human monocyte-derived dendritic cells (MoDCs). The aim of this approach is the selection of potential immunotherapeutic small molecules from natural extracts or chemical libraries.
Oxygenated Theonellastrols: Interpretation of Unusual Chemical Behaviors Using Quantum Mechanical Calculations and Stereochemical Reassignment of 7α-Hydroxytheonellasterol
Authors: Shin A-Young , Lee Hyi-Seung , Lee Yeon-Ju , Lee Jong Seok , Son Arang , Choi Changhoon , Lee Jihoon
Published: November 2020

A total of eight new oxygenated 4-exo-methylene sterols, 1–8, together with one artifact 9 and six known sterols 11–16, were isolated from the marine sponge Theonella swinhoei collected from the Bohol province in Philippines. Structures of sterols 1–8 were determined from 1D and 2D NMR data. Among the sterols, 8α-hydroxytheonellasterol (4) spontaneously underwent an allylic 1,3-hydroxyl shift to produce 15α-hydroxytheonellasterol (9) as an artifact; this was rationalized by quantum mechanical calculations of the transition state. In addition, the 1,2-epoxy alcohol subunit of 8α-hydroxy-14,15-β-epoxytheonellasterol (5) was assigned using the Gauge-Independent Atomic Orbital (GIAO) NMR chemical shift calculations and subsequent DP4+ analysis. Finally, comparison of the 13C chemical shifts of isolated 7α-hydroxytheonellasterol (6) with the reported values revealed significant discrepancies at C-6, C-7, C-8, and C-14, leading to reassignment of the C-7 stereochemistry in the known structure.
Factors Associated with the Delayed Termination of Viral Shedding in COVID-19 Patients with Mild Severity in South Korea
Authors: Kim Bongyoung , Sohn Jang Wook , Nam Soomin , Sohn Jang Won , Choi Won Suk , Kim Hyoung Seop
Published: November 2020

Background and objectives: We aimed to analyze factors associated with the period of viral shedding in patients with confirmed COVID-19 who experienced only mild symptoms. Materials and methods: We conducted a multicenter retrospective study from three community treatment centers (CTCs) of South Korea. All patients included were admitted to the three centers before 31 March 2020. We collected data about clinical characteristics and the result of real-time reverse transcription polymerase chain reaction (RT-PCR). Results: Viral shedding was terminated within 32 days and 36 days in 75% and 90% of patients, respectively (range: 8–49 days). The mean period of viral shedding was 23.8 ± 8.7 days. In the multivariate Cox proportional hazards regression analysis, the existence of underlying comorbidities lowered the probability of the termination of viral shedding (HR = 0.561, 95% CI 0.388–0.812). Female sex and presence of COVID-19-associated symptoms also lowered the probability, but the significance was marginal. Conclusions: The existence of underlying comorbidities was associated with delayed termination of viral shedding in COVID-19 patients with mild severity.
Health-Related Quality of Life in Stroke Survivors in Relation to the Type of Inpatient Rehabilitation in Serbia: A Prospective Cohort Study
Authors: Rancic Natasa K. , Mandic Milan N. , Kocic Biljana N. , Veljkovic Dejan R. , Kocic Ilija D. , Otasevic Suzana A.
Published: November 2020

Background and objectives: Health-related quality of life after stroke is an important public health issue. The objective of the study was to investigate the relationship between the perceived health-related quality of life in stroke survivors in relation to the type of inpatient rehabilitation. Materials and Methods: Using a random selection method out of a total of 688 patients, every fourth survivor who had a stroke in the period from 1 January 2017 to 31 December 2019 was selected from the admission protocol of the Clinic for Rehabilitation and Physical Medicine of the Clinical Centre Niš, Serbia. A total of 160 first-ever stroke survivors were included (80 underwent additional inpatient rehabilitation and 80 underwent only inpatient rehabilitation in a tertiary health institution) in a twelve-month prospective study. The EuroQuol-5 Dimension (EQ5D) questionnaire and Stroke Impact Scale were used for the assessment. Multivariate linear regression analysis was done. Results: Multivariate linear regression analysis showed that additional inpatient rehabilitation from six up to eight weeks after discharge was significantly associated with better self-reported health condition by 3.9 times (from 1.9 to 8.2), significantly decreased the ranks of EQ5D by 1.78 times (from 1.02 to 3.11), and showed a higher health-related quality of life. We determined a significant increase of strength, emotions, mobility, and participation role in survivors who underwent additional inpatient rehabilitation compared with those who did not. Conclusions: There was a significant difference in health-related quality of life perceived by stroke survivors who underwent additional hospital rehabilitation in relation to those who underwent only inpatient rehabilitation.
Research Progress in Gas Separation Using Hollow Fiber Membrane Contactors
Authors: Li Linlin , Ma Guiyang , Pan Zhen , Zhang Na , Zhang Zhien
Published: November 2020

In recent years, gas–liquid membrane contactors have attracted increasing attention. A membrane contactor is a device that realizes gas–liquid or liquid–liquid mass transfer without being dispersed in another phase. The membrane gas absorption method combines the advantages of chemical absorption and membrane separation, in addition to exhibiting high selectivity, modularity, and compactness. This paper introduces the operating principle and wetting mechanism of hollow membrane contactors, shows the latest research progress of membrane contactors in gas separation, especially for the removal of carbon dioxide from gas mixtures by membrane contactors, and summarizes the main aspects of membrane materials, absorbents, and membrane contactor structures. Furthermore, recommendations are provided for the existing deficiencies or unsolved problems (such as membrane wetting), and the status and progress of membrane contactors are discussed.
Energy Storage Behavior of Lithium-Ion Conducting poly(vinyl alcohol) (PVA): Chitosan(CS)-Based Polymer Blend Electrolyte Membranes: Preparation, Equivalent Circuit Modeling, Ion Transport Parameters, and Dielectric Properties
Authors: Brza Mohamad , Aziz Shujahadeen B. , Raza Saeed Salah , Hamsan Muhamad H. , Majid Siti Rohana , Abdulwahid Rebar T. , Kadir Mohd F. Z. , Abdullah Ranjdar M.
Published: November 2020

Plasticized lithium-ion-based-conducting polymer blend electrolytes based on poly(vinyl alcohol) (PVA):chitosan (CS) polymer was prepared using a solution cast technique. The conductivity of the polymer electrolyte system was found to be 8.457 × 10−4 S/cm, a critical factor for electrochemical device applications. It is indicated that the number density (n), diffusion coefficient (D), and mobility (μ) of ions are increased with the concentration of glycerol. High values of dielectric constant and dielectric loss were observed at low frequency region. A correlation was found between the dielectric constant and DC conductivity. The achieved transference number of ions (tion) and electrons (te) for the highest conducting plasticized sample were determined to be 0.989 and 0.011, respectively. The electrochemical stability for the highest conducting sample was 1.94 V, indicated by linear sweep voltammetry (LSV). The cyclic voltammetry (CV) response displayed no redox reaction peaks through its entire potential range. Through the constructing electric double-layer capacitor, the energy storage capacity of the highest conducting sample was investigated. All decisive parameters of the EDLC were determined. At the first cycle, the specific capacitance, internal resistance, energy density, and power density were found to be 130 F/g, 80 Ω, 14.5 Wh/kg, and 1100 W/kg, respectively.