bluuebunny/crossref_metadata_2025 huggingface dataset:
Dietary Habits and Gut Microbiota in Healthy Adults: Focusing on the Right Diet. A Systematic Review
Authors: Gibiino Giulia , De Siena Martina , Sbrancia Monica , Binda Cecilia , Sambri Vittorio , Gasbarrini Antonio , Fabbri Carlo
Published: June 2021

Diet is the first to affect our intestinal microbiota and therefore the state of eubiosis. Several studies are highlighting the potential benefits of taking certain nutritional supplements, but a dietary regime that can ensure the health of the intestinal microbiota, and the many pathways it governs, is not yet clearly defined. We performed a systematic review of the main studies concerning the impact of an omnivorous diet on the composition of the microbiota and the production of short-chain fatty acids (SCFAs). Some genera and phyla of interest emerged significantly and about half of the studies evaluated consider them to have an equally significant impact on the production of SCFAs, to be a source of nutrition for our colon cells, and many other processes. Although numerous randomized trials are still needed, the Mediterranean diet could play a valuable role in ensuring our health through direct interaction with our microbiota.
Phototoxicities Caused by Continuous Light Exposure Were Not Induced in Retinal Ganglion Cells Transduced by an Optogenetic Gene
Authors: Tabata Kitako , Sugano Eriko , Hatakeyama Akito , Watanabe Yoshito , Suzuki Tomoya , Ozaki Taku , Fukuda Tomokazu , Tomita Hiroshi
Published: June 2021

The death of photoreceptor cells is induced by continuous light exposure. However, it is unclear whether light damage was induced in retinal ganglion cells with photosensitivity by transduction of optogenetic genes. In this study, we evaluated the phototoxicities of continuous light exposure on retinal ganglion cells after transduction of the optogenetic gene mVChR1 using an adeno-associated virus vector. Rats were exposed to continuous light for a week, and visually evoked potentials (VEPs) were recorded. The intensities of continuous light (500, 1000, 3000, and 5000 lx) increased substantially after VEP recordings. After the final recording of VEPs, retinal ganglion cells (RGCs) were retrogradely labeled with a fluorescein tracer, FluoroGold, and the number of retinal ganglion cells was counted under a fluorescent microscope. There was no significant reduction in the amplitudes of VEPs and the number of RGCs after exposure to any light intensity. These results indicated that RGCs were photosensitive after the transduction of optogenetic genes and did not induce any phototoxicity by continuous light exposure.
CYLD Inhibits the Development of Skin Squamous Cell Tumors in Immunocompetent Mice
Authors: Alameda Josefa P. , García-García Verónica A. , López Silvia , Hernando Ana , Page Angustias , Navarro Manuel , Moreno-Maldonado Rodolfo , Paramio Jesús M. , Ramírez Ángel , García-Fernández Rosa A. , Casanova María Llanos
Published: June 2021

Cylindromatosis (CYLD) is a deubiquitinase (DUB) enzyme that was initially characterized as a tumor suppressor of adnexal skin tumors in patients with CYLD syndrome. Later, it was also shown that the expression of functionally inactive mutated forms of CYLD promoted tumor development and progression of non-melanoma skin cancer (NMSC). However, the ability of wild-type CYLD to inhibit skin tumorigenesis in vivo in immunocompetent mice has not been proved. Herein, we generated transgenic mice that express the wild type form of CYLD under the control of the keratin 5 (K5) promoter (K5-CYLDwt mice) and analyzed the skin properties of these transgenic mice by WB and immunohistochemistry, studied the survival and proliferating characteristics of primary keratinocytes, and performed chemical skin carcinogenesis experiments. As a result, we found a reduced activation of the nuclear factor kappa B (NF-κB) pathway in the skin of K5-CYLDwt mice in response to tumor necrosis factor-α (TNF-α); accordingly, when subjected to insults, K5-CYLDwt keratinocytes are prone to apoptosis and are protected from excessive hyperproliferation. Skin carcinogenesis assays showed inhibition of tumor development in K5-CYLDwt mice. As a mechanism of this tumor suppressor activity, we found that a moderate increase in CYLD expression levels reduced NF-κB activation, which favored the differentiation of tumor epidermal cells and inhibited its proliferation; moreover, it decreased tumor angiogenesis and inflammation. Altogether, our results suggest that increased levels of CYLD may be useful for anti-skin cancer therapy.
Effect of Fibrin Concentration on the In Vitro Production of Dermo-Epidermal Equivalents
Authors: Montero Andrés , Quílez Cristina , Valencia Leticia , Girón Paula , Jorcano José Luis , Velasco Diego
Published: June 2021

Human plasma-derived bilayered skin substitutes were successfully used by our group to produce human-based in vitro skin models for toxicity, cosmetic, and pharmaceutical testing. However, mechanical weakness, which causes the plasma-derived fibrin matrices to contract significantly, led us to attempt to improve their stability. In this work, we studied whether an increase in fibrin concentration from 1.2 to 2.4 mg/mL (which is the useful fibrinogen concentration range that can be obtained from plasma) improves the matrix and, hence, the performance of the in vitro skin cultures. The results show that this increase in fibrin concentration indeed affected the mechanical properties by doubling the elastic moduli and the maximum load. A structural analysis indicated a decreased porosity for the 2.4 mg/mL hydrogels, which can help explain this mechanical behavior. The contraction was clearly reduced for the 2.4 mg/mL matrices, which also allowed for the growth and proliferation of primary fibroblasts and keratinocytes, although at a somewhat reduced rate compared to the 1.2 mg/mL gels. Finally, both concentrations of fibrin gave rise to organotypic skin cultures with a fully differentiated epidermis, although their lifespans were longer (25–35%) in cultures with more concentrated matrices, which improves their usefulness. These systems will allow the generation of much better in vitro skin models for the testing of drugs, cosmetics and chemicals, or even to “personalized” skin for the diagnosis or determination of the most effective treatment possible.
Changes in the Cell Wall Proteome of Leaves in Response to High Temperature Stress in Brachypodium distachyon
Authors: Pinski Artur , Betekhtin Alexander , Skupien-Rabian Bozena , Jankowska Urszula , Jamet Elisabeth , Hasterok Robert
Published: June 2021

High temperature stress leads to complex changes to plant functionality, which affects, i.a., the cell wall structure and the cell wall protein composition. In this study, the qualitative and quantitative changes in the cell wall proteome of Brachypodium distachyon leaves in response to high (40 °C) temperature stress were characterised. Using a proteomic analysis, 1533 non-redundant proteins were identified from which 338 cell wall proteins were distinguished. At a high temperature, we identified 46 differentially abundant proteins, and of these, 4 were over-accumulated and 42 were under-accumulated. The most significant changes were observed in the proteins acting on the cell wall polysaccharides, specifically, 2 over- and 12 under-accumulated proteins. Based on the qualitative analysis, one cell wall protein was identified that was uniquely present at 40 °C but was absent in the control and 24 proteins that were present in the control but were absent at 40 °C. Overall, the changes in the cell wall proteome at 40 °C suggest a lower protease activity, lignification and an expansion of the cell wall. These results offer a new insight into the changes in the cell wall proteome in response to high temperature.
The Impact of Exercise Serum on Selected Parameters of CD4+ T Cell Metabolism
Authors: Palmowski Jana , Gebhardt Kristina , Reichel Thomas , Frech Torsten , Ringseis Robert , Eder Klaus , Renner-Sattler Kathrin , Krüger Karsten
Published: June 2021

CD4+ T cells are sensitive to peripheral changes of cytokine levels and metabolic substrates such as glucose and lactate. This study aimed to analyze whether factors released after exercise alter parameters of human T cell metabolism, specifically glycolysis and oxidative phosphorylation. We used primary human CD4+ T cells activated in the presence of autologous serum, which was collected before (CO) and after a 30-min exercise intervention (EX). In the course of activation, cells and supernatants were analyzed for cell viability and diameter, real-time oxygen consumption by using PreSens Technology, mRNA expression of glycolytic enzymes and complexes of the electron transport chain by real-time PCR, glucose, and lactate levels in supernatants, and in vitro differentiation by flow cytometry. EX did not alter T cell phenotype, viability, or on-blast formation. Similarly, no difference between CO and EX were found for CD4+ T cell activation and cellular oxygen consumption. In contrast, higher levels of glucose were found after 48 h activation in EX conditions. T cells activated in autologous exercise serum expressed lower HK1 mRNA and higher IFN-γ receptor 1. We suggest that the exercise protocol used was not sufficient to destabilize the immune metabolism of T cells. Therefore, more intense and prolonged exercise should be used in future studies.
Is There a Futility Discriminant Function Score for Alcoholic Hepatitis?
Authors: Lamm Kevin , McCarter Maggie , Russo Mark W.
Published: June 2021

The treatment for patients with alcoholic hepatitis (AH) who have a discriminant function (DF) score greater than 32 has been steroids. A prior study reported that mortality approaches 100% when the DF score is greater than 54, despite the use of prednisolone. Our aim was to determine if a DF score greater than 54 is associated with high mortality despite steroids. We conducted a retrospective study of 531 first-time inpatient encounters of AH. We compared 30-day mortality between patients with DF 54 or less to those greater than 54 treated with steroids, as well as a matched group not treated with steroids. A total of 531 inpatients diagnosed with AH were identified, of which 124 had a DF greater than 32 and 52 were treated with steroids. Among patients treated with steroids, 30-day mortality for patients with DF greater than 54 (n = 27) and 54 or below (n = 25) was 22% and 12%, respectively (p = 0.47). Among patients with DF greater than 54, the 30-day mortality for those who did (n = 27) and did not (n = 29) receive steroids was 22% and 24%, respectively (p = 0.87). In our study population, steroids were not futile in patients with a DF score of greater than 54.
Deciphering Exhaled Aerosol Fingerprints for Early Diagnosis and Personalized Therapeutics of Obstructive Respiratory Diseases in Small Airways
Authors: Si Xiuhua April , Xi Jinxiang
Published: June 2021

Respiratory diseases often show no apparent symptoms at their early stages and are usually diagnosed when permanent damages have been made to the lungs. A major site of lung pathogenesis is the small airways, which make it highly challenging to detect using current techniques due to the diseases’ location (inaccessibility to biopsy) and size (below normal CT/MRI resolution). In this review, we present a new method for lung disease detection and treatment in small airways based on exhaled aerosols, whose patterns are uniquely related to the health of the lungs. Proof-of-concept studies are first presented in idealized lung geometries. We subsequently describe the recent developments in feature extraction and classification of the exhaled aerosol images to establish the relationship between the images and the underlying airway remodeling. Different feature extraction algorithms (aerosol density, fractal dimension, principal mode analysis, and dynamic mode decomposition) and machine learning approaches (support vector machine, random forest, and convolutional neural network) are elaborated upon. Finally, future studies and frequent questions related to clinical applications of the proposed aerosol breath testing are discussed from the authors’ perspective. The proposed breath testing has clinical advantages over conventional approaches, such as easy-to-perform, non-invasive, providing real-time feedback, and is promising in detecting symptomless lung diseases at early stages.
Not Only a Formulation: The Effects of Pickering Emulsion on the Entomopathogenic Action of Metarhizium brunneum
Authors: Birnbaum Nitsan , Reingold Victoria , Matveev Sabina , Kottakota Chandrasekhar , Davidovitz Michael , Mani Karthik Ananth , Feldbaum Reut , Yaakov Noga , Mechrez Guy , Ment Dana
Published: June 2021

Growing global population and environmental concerns necessitate the transition from chemical to eco-friendly pest management. Entomopathogenic fungi (EPF) are rising candidates for this task due to their ease of growing, broad host range and unique disease process, allowing EPF to infect hosts directly through its cuticle. However, EPF’s requirement for high humidity negates their integration into conventional agriculture. To mitigate this problem, we formulated Metarhizium brunneum conidia in an oil-in-water Pickering emulsion. Conidia in aqueous and emulsion formulations were sprayed on Ricinus communis leaves, and Spodoptera littoralis larvae were introduced under low or high humidity. The following were examined: conidial dispersion on leaf, larval mortality, conidial acquisition by larvae, effects on larval growth and feeding, and dynamic of disease progression. Emulsion was found to disperse conidia more efficiently and caused two-fold more adhesion of conidia to host cuticle. Mortality from conidia in emulsion was significantly higher than other treatments reaching 86.5% under high humidity. Emulsion was also found to significantly reduce larval growth and feeding, while conferring faster fungal growth in-host. Results suggest that a Pickering emulsion is able to improve physical interactions between the conidia and their surroundings, while weakening the host through a plethora of mechanisms, increasing the chance of an acute infection.
Association between Obstructive Lung Disease and Cardiovascular Disease: Results from the Vermont Diabetes Information System
Authors: Ramos-Nino Maria E. , MacLean Charles D. , Littenberg Benjamin
Published: June 2021

The association between obstructive lung disease and cardiovascular disease (CVD) has been suggested previously, but few studies have looked at this association in a diabetic cohort, a population highly susceptible to both comorbidities. A total of 1003 subjects in community practice settings were interviewed at home at the time of enrolment into the Vermont Diabetes Information System, a clinical decision support program. Patients self-reported their personal and clinical characteristics, including any obstructive lung disease. Laboratory data were obtained directly from the clinical laboratory. We performed a cross-sectional analysis of the interviewed subjects to assess a possible association between obstructive lung disease and CVD. In a multivariate logistic regression model, obstructive lung disease was significantly associated with CVD, even after correcting for potential confounders, including gender, obesity, low income, cigarette smoking, alcohol problems, and high comorbidity (odds ratio = 1.96; 95% confidence interval 1.37–2.81; p < 0.01). All components of CVD, including coronary artery disease (CAD), congestive heart failure (CHF), peripheral vascular disease (PVD), and cerebrovascular accidents (CVA), were also significantly associated with obstructive lung disease. These data suggest an association between obstructive lung disease and CVD in patients with diabetes. Future studies are needed to identify the mechanism supporting this association
Volatility Spillover and International Contagion of Housing Bubbles
Authors: Bago Jean-Louis , Akakpo Koffi , Rherrad Imad , Ouédraogo Ernest
Published: June 2021

This paper provides new empirical evidence on housing bubble timing, volatility spillover, and bubble contagion between Japan and its economic partners, namely, the United States, the Eurozone, and the United Kingdom. First, we apply a generalized sup ADF (GSADF) test to the quarterly price-to-rent ratio from 1970Q1 to 2018Q4 to detect explosive behaviors in housing prices. Second, we analyze the volatility spillover in housing prices between Japan and its economic partners using the multivariate time-varying DCC-GARCH model. Third, we assess bubble contagion by estimating a non-parametric model of bubble migration with time-varying coefficients. We document two historical bubble episodes from 1970 to 2018 in Japan’s housing market. Moreover, we find evidence of volatility spillover effects and bubble contagion between Japan’s real estate market and its most important economic partners during several periods. In this context of market integration, countries need to develop coordinated real estate policies to address the risk of global real estate bubbles.
Stress-Related Regulation Is Abnormal in the Psoriatic Uninvolved Skin
Authors: Bozó Renáta , Danis Judit , Flink Lili Borbála , Vidács Dániel László , Kemény Lajos , Bata-Csörgő Zsuzsanna
Published: June 2021

Keratinocyte stress-response of the uninvolved psoriatic epidermis is known to be altered compared to healthy cells. Therefore, we aimed to reveal potential mechanisms underlying this alteration. We compared the expression of annotated cell-stress-related proteins between uninvolved psoriatic and healthy skin using the protein array method. Data were analyzed by the Reactome over-representation test. We found that p27/CDKN1B and cytochrome C showed at least a two-fold increase, while cyclooxygenase-2, indolamine-2,3-dioxygenase-1, serum paraoxonase 1, serum paraoxonase 3, serine-46-phosphorylated tumor protein p53, and superoxide-dismutase-2 showed a two-fold decrease in expression in the uninvolved skin. Over-representation analysis suggested the Forkhead-box protein O (FOXO)-mediated transcription as the most significant pathway affected by the differently expressed cell-stress-related proteins (DECSRPs). DECSRPs indicate increased FOXO-mediated transcription of cell-cycle genes and reduced interleukin-signaling in the psoriatic uninvolved skin. Nuclear positivity of the FOXO-signaling-related p27/CDKN1B and FOXO1 are negatively correlated with the disease severity and showed increased expression in the uninvolved epidermis and also in healthy primary keratinocytes, which were grown on cartilage oligomeric matrix protein-coated surfaces. Our results indicate a cell-cycle inhibitory process, as a stress-related compensatory mechanism in the uninvolved epidermis, that could be responsible for blocking keratinocyte hyperproliferation in the psoriatic uninvolved skin, thus maintaining the symptomless skin phenotype.
Transarterial Chemoembolization of Hepatocellular Carcinoma with Oncozene Microspheres: An Initial, Short-Term Clinical Experience—A Retrospective, Matched, Comparison Study
Authors: Hung Matthew L. , Jiang Jerry , Trieu Harry , Hao Frank , Eghbalieh Navid , Ding Peng-Xu , Lee Edward Wolfgang
Published: June 2021

Background: The purpose of this study is to describe a single institution’s experience using Oncozene (OZ) microspheres for transarterial chemoembolization (OZ-TACE) of hepatocellular carcinoma (HCC), and to compare tolerability, safety, short-term radiographic tumor response, progression-free survival (PFS), and overall survival (OS) of these procedures to TACE (LC-TACE) performed with LC beads (LC). Methods: A retrospective, matched cohort study of patients undergoing DEB-TACE (drug-eluting bead transarterial chemoembolization) with OZ or LC was performed. The cohort comprised 23 patients undergoing 29 TACE with 75 or 100 μm OZ and 24 patients undergoing 29 TACE with 100–300 μm LC. Outcome measures were changes in liver function tests, complications, treatment tolerability, short-term radiographic tumor response according to modified RECIST criteria for HCC, PFS, and 1-year OS. The Mann–Whitney U test, Fisher exact test, and log rank test were used to compare the groups. Results: The BCLC or Child–Pugh scores were similar between the OZ and LC group. However, the two groups differed with respect to the etiology of background cirrhosis (p = 0.02). All other initial demographic and tumor characteristics were similar between the two groups. OZ-TACE used less doxorubicin per treatment compared to LC-TACE (median 50 vs. 75 mg; p = 0.0005). Rates of pain, nausea, and postembolization syndrome were similar, irrespective of the embolic agent used. OZ-TACE resulted in an overall complication rate comparable to LC-TACE (20.7% vs. 10.3%; p = 0.47). LC-TACE resulted in a higher percent increase in total bilirubin on post-procedure day 1 (median 18.8 vs. 0%; p = 0.05), but this difference resolved at 1 month. Both OZ-TACE and LC-TACE resulted in similar complete (31% vs. 24%) and objective (66% vs. 79%) target lesion response rates on 1-month post-TACE imaging. Both OZ-TACE and LC-TACE had similar median progression-free survival (283 vs. 209 days; p = 0.14) and 1-year overall survival rates (85% vs. 76%; p = 0.30). Conclusion: With a significantly reduced dose of doxorubicin, TACE performed with Oncozene microspheres in a heterogeneous patient population is well-tolerated, safe, and produces a similar radiological response and survival rate when compared to LC Bead TACE.
Multidrug Resistence Prevalence in COVID Area
Authors: Aurilio Caterina , Sansone Pasquale , Paladini Antonella , Barbarisi Manlio , Coppolino Francesco , Pota Vincenzo , Pace Maria Caterina
Published: June 2021

Coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2, is often complicated by severe acute respiratory syndrome. The new coronavirus outbreak started in China in December 2019 and rapidly spread around the world. The high diffusibility of the virus was the reason for the outbreak of the pandemic viral disease, reaching more than 100 million infected people globally by the first three months of 2021. In the various treatments used up to now, the use of antimicrobial drugs for the management, especially of bacterial co-infections, is very frequent in patients admitted to intensive care. In addition, critically ill patients with SARS-CoV-2 infection are subjected to prolonged mechanical ventilation and other therapeutic procedures often responsible for developing hospital co-infections due to multidrug-resistant bacteria. Co-infections contribute to the increase in the morbidity–mortality of viral respiratory infections. We performed this study to review the recent articles published on the antibiotic bacterial resistance and viruses to predict risk factors of coronavirus disease 2019 and to assess the multidrug resistance in patients hospitalized in the COVID-19 area.
Wireless Capsule Endoscopy for Diagnosis and Management of Post-Operative Recurrence of Crohn’s Disease
Authors: Mir Adil , Nguyen Vu Q. , Soliman Youssef , Sorrentino Dario
Published: June 2021

Despite aggressive medical therapy, many patients with Crohn’s disease require surgical intervention over time. After surgical resection, disease recurrence is common. Ileo-colonoscopy and the Rutgeerts score are commonly used for diagnosis and monitoring of post-operative endoscopic recurrence. The latter is the precursor of clinical recurrence and therefore it impacts prognosis and patient management. However, due to the limited length of bowel assessed by ileo-colonoscopy, this procedure can miss out-of-reach, more proximal lesions in the small bowel. This limitation introduces an important uncertainty when evaluating post-operative relapse by ileo-colonoscopy. In addition, the Rutgeerts score ‘per se’ bears a number of ambiguities. Here we will discuss the pros and cons of ileo-colonoscopy and other imaging studies including wireless capsule endoscopy to diagnose and manage post-operative recurrence of Crohn’s disease. A number of studies provide evidence that wireless capsule endoscopy is a potentially more accurate as well as less invasive and less costly alternative to conventional techniques including ileo-colonoscopy.
Role of Intestinal Ultrasound in the Management of Patients with Inflammatory Bowel Disease
Authors: Jauregui-Amezaga Aranzazu , Rimola Jordi
Published: June 2021

Intestinal ultrasound (IUS) has gained popularity as a first line technique for the diagnosis and monitoring of patients with inflammatory bowel diseases (IBD) due to its many advantages. It is a non-invasive imaging technique with non-ionizing radiation exposure. It can be easily performed not only by radiologists but also by trained gastroenterologists at outpatient clinics. In addition, the cost of IUS equipment is low when compared with other imaging techniques. IUS is an accurate technique to detect inflammatory lesions and complications in the bowel in patients with suspected or already known Crohn’s disease (CD). Recent evidence indicates that IUS is a convenient and accurate technique to assess extension and activity in the colon in patients with ulcerative colitis (UC), and can be a non-invasive alternative to endoscopy. In patients with IBD, several non-specific pathological ultrasonographic signs can be identified: bowel wall thickening, alteration of the bowel wall echo-pattern, loss of bowel stratification, increased vascularization, decreased bowel peristalsis, fibro-fatty proliferation, enlarged lymph nodes, and/or abdominal free fluid. Considering the transmural CD inflammation, CD complications such as presence of strictures, fistulae, or abscesses can be detected. In patients with UC, where inflammation is limited to mucosa, luminal inflammatory ultrasonographic changes are similar to those of CD. As the technique is related to the operator’s experience, adequate IUS training, performance in daily practice, and a generalized use of standardized parameters will help to increase its reproducibility.
Mitochondrial Dynamics in Drug-Induced Liver Injury
Authors: Ramachandran Anup , Umbaugh David S. , Jaeschke Hartmut
Published: June 2021

Mitochondria have been studied for decades from the standpoint of metabolism and ATP generation. However, in recent years mitochondrial dynamics and its influence on bioenergetics and cellular homeostasis is also being appreciated. Mitochondria undergo regular cycles of fusion and fission regulated by various cues including cellular energy requirements and pathophysiological stimuli, and the network of critical proteins and membrane lipids involved in mitochondrial dynamics is being revealed. Hepatocytes are highly metabolic cells which have abundant mitochondria suggesting a biologically relevant role for mitochondrial dynamics in hepatocyte injury and recovery. Here we review information on molecular mediators of mitochondrial dynamics and their alteration in drug-induced liver injury. Based on current information, it is evident that changes in mitochondrial fusion and fission are hallmarks of liver pathophysiology ranging from acetaminophen-induced or cholestatic liver injury to chronic liver diseases. These alterations in mitochondrial dynamics influence multiple related mitochondrial responses such as mitophagy and mitochondrial biogenesis, which are important adaptive responses facilitating liver recovery in several contexts, including drug-induced liver injury. The current focus on characterization of molecular mechanisms of mitochondrial dynamics is of immense relevance to liver pathophysiology and have the potential to provide significant insight into mechanisms of liver recovery and regeneration after injury.
Calibration of Failure Criteria for Additively Manufactured Metallic Materials
Authors: Socha Grzegorz
Published: June 2021

A new version of failure criterion for additively manufactured materials, together with simple and accurate calibration procedures, is proposed and experimentally verified in this paper. The proposition is based on void growth-based ductile failure models. The failure criterion for ductile materials proposed by Hancock–Mackenzie was calibrated using simple methods and accessories. The calibration procedure allows the determination of failure strain under pure shear. The method is accurate and simple due to the fact that it prevents strain localization disturbing stress distribution at the failure zone. The original criterion was modified to better suit the deformation behavior of additively manufactured materials. Examples of calibration of the original and modified failure criteria for additively manufactured 316L alloy steel is also given in this paper, along with analyses of the obtained results.
EPR Spectra of Sintered Cd1−xCrxTe Powdered Crystals with Various Cr Content
Authors: Stefaniuk Ireneusz , Obermayr Werner , Popovych Volodymyr D. , Cieniek Bogumił , Rogalska Iwona
Published: June 2021

In this paper, we show a simple method of producing ferromagnetic materials with a Curie temperature above room temperature. The electron paramagnetic resonance (EPR) spectra of Cd1−xCrxTe (0.002 < x < 0.08) were measured with a dependence on temperature (82 K < T < 381 K). Obtained EPR lines were fitted to a Lorentz-shaped curve. The temperature dependencies of the parameters of the EPR lines, such as the peak-to-peak linewidth (Hpp), the intensity (A), as well as the resonance field (Hr), were studied. Ferromagnetism was noticed in samples at high temperatures (near room temperature). For a sample with a nominal concentration of chrome of x = 0.05, a very strong intrinsic magnetic field is observed. The value of the effective gyromagnetic factor for this sample is ge = 30 at T = 240 K. An increase of chrome concentration above x = 0.05 reduces the ferromagnetic properties considerably. Analysis of the temperature dependencies of the integral intensity of EPR spectra was carried out using the Curie–Weiss law and the paramagnetic Curie temperature was obtained.
Use of the AE Effect to Determine the Stresses State in AAC Masonry Walls under Compression
Authors: Jasiński Radosław , Stebel Krzysztof , Kielan Paweł
Published: June 2021

Safety and reliability of constructions operated are predicted using the known mechanical properties of materials and geometry of cross-sections, and also the known internal forces. The extensometry technique (electro-resistant tensometers, wire gauges, sensor systems) is a common method applied under laboratory conditions to determine the deformation state of a material. The construction sector rarely uses ultrasonic extensometry with the acoustoelastic (AE) method which is based on the relation between the direction of ultrasonic waves and the direction of normal stresses. It is generally used to identify stress states of machine or vehicles parts, mainly made of steel, characterized by high homogeneity and a lack of inherent internal defects. The AE effect was detected in autoclaved aerated concrete (AAC), which is usually used in masonry units. The acoustoelastic effect was used in the tests described to identify the complex stress state in masonry walls (masonry units) made of AAC. At first, the relationships were determined for mean hydrostatic stresses P and mean compressive stresses σ3 with relation to velocities of the longitudinal ultrasonic wave cp. These stresses were used to determine stresses σ3. The discrete approach was used which consists in analyzing single masonry units. Changes in velocity of longitudinal waves were identified at a test stand to control the stress states of an element tested by the digital image correlation (DIC) technique. The analyses involved density and the impact of moisture content of AAC. Then, the method was verified on nine walls subjected to axial compression and the model was validated with the FEM micromodel. It was demonstrated that mean compressive stresses σ3 and hydrostatic stresses, which were determined for the masonry using the method considered, could be determined even up to ca. 75% of failure stresses at the acceptable error level of 15%. Stresses σ1 parallel to bed joints were calculated using the known mean hydrostatic stresses and mean compressive stresses σ3.
Design and Development of Cellulosic Bionanocomposites from Forestry Waste Residues for 3D Printing Applications
Authors: John Maya Jacob , Dyanti Nokuzola , Mokhena Teboho , Agbakoba Victor , Sithole Bruce
Published: June 2021

This paper deals with the development of cellulose nanofibres (CNFs) reinforced biopolymers for use in packaging applications. Cellulose nanofibres were extracted from sawdust by a combination of chemical and mechanical treatments. The extracted cellulose nanofibres were chemically modified (fCNFs) and characterised by Fourier Transform Infrared Spectroscopy (FTIR). Bionanocomposites were prepared from biopolymers polylactic acid/polybutylene succinate (PLA/PBS) and cellulose nanofibres by compounding in a twin-screw extruder followed by injection moulding. The developed bionanocomposites were subjected to mechanical and thermal characterisation. As part of product development, CNF-biopolymer pellets were also extruded into filaments which were then 3D printed into prototypes. This work is a successful demonstration of conversion of waste residues into value-added products, which is aligned to the principles of circular economy and sustainable development.
Research on the Ignition Height and Reaction Flame Temperature of PTFE/Al/Si/CuO with Different Mass Ratios of PTFE/Si
Authors: Zou Xuan , Zhou Jingyuan , Ran Xianwen , Wu Yiting , Liu Ping , Tang Wenhui , Chen Pengwan , Wang Haifu
Published: June 2021

Recent studies have shown that the energy release capacity of Polytetrafluoroethylene (PTFE)/Al with Si, and CuO, respectively, is higher than that of PTFE/Al. PTFE/Al/Si/CuO reactive materials with four proportions of PTFE/Si were designed by the molding–sintering process to study the influence of different PTFE/Si mass ratios on energy release. A drop hammer was selected for igniting the specimens, and the high-speed camera and spectrometer systems were used to record the energy release process and the flame spectrum, respectively. The ignition height of the reactive material was obtained by fitting the relationship between the flame duration and the drop height. It was found that the ignition height of PTFE/Al/Si/CuO containing 20% PTFE/Si is 48.27 cm, which is the lowest compared to the ignition height of other Si/PTFE ratios of PTFE/Al/Si/CuO; the flame temperature was calculated from the flame spectrum. It was found that flame temperature changes little for the same reactive material at different drop heights. Compared with the flame temperature of PTFE/Al/Si/CuO with four mass ratios, it was found that the flame temperature of PTFE/Al/Si/CuO with 20% PTFE/Si is the highest, which is 2589 K. The results show that PTFE/Al/Si/CuO containing 20% PTFE/Si is easier to be ignited and has a stronger temperature destruction effect.
Mechanical and Gamma Ray Absorption Behavior of PbO-WO3-Na2O-MgO-B2O3 Glasses in the Low Energy Range
Authors: Almuqrin Aljawhara H. , Albarzan Badriah , Olarinoye O. I. , Kumar Ashok , Alwadai Norah , Sayyed M. I.
Published: June 2021

The Makishima and Mackenzie model has been used to determine the mechanical properties of the PbO-WO3-Na2O-MgO-B2O3 glass system. The number of bonds per unit volume of the glasses (nb) increases from 9.40 × 1022 to 10.09 × 1022 cm−3 as the PbO content increases from 30 to 50 mol%. The Poisson’s ratio (σ) for the examined glasses falls between 0.174 and 0.210. The value of the fractal bond connectivity (d) for the present glasses ranges from 3.08 to 3.59. Gamma photon and fast neutron shielding parameters were evaluated via Phy-X/PSD, while that of electrons were calculated via the ESTAR platform. Analysis of the parameters showed that both photon and electron attenuation ability improve with the PbO content. The fast neutron removal cross section of the glasses varies from 0.094–0.102 cm−1 as PbO molar content reduced from 50–30 mol%. Further analysis of shielding parameters of the investigated glass system showed that they possess good potential to function in radiation protection applications.
Experimental Study on High-Speed Milling of SiCf/SiC Composites with PCD and CVD Diamond Tools
Authors: Zhang Bin , Du Yanan , Liu Hanliang , Xin Lianjia , Yang Yinfei , Li Liang
Published: June 2021

Silicon carbide fiber reinforced silicon carbide ceramic matrix composite (SiCf/SiC composite) is characterized by a high strength-to-density ratio, high hardness, and high temperature resistance. However, due to the brittleness of the matrix material and the anisotropy of the reinforcing phase, it is a huge challenge for machining of the material. The milling method has advantages of a high material removal rate and applicability to complex surface geometry. However, no published literature on milling of SiCf/SiC composite has been found up to now. In this paper, high-speed milling of SiCf/SiC composites was carried out under dry conditions and cryogenic cooling using liquid nitrogen, respectively. Polycrystalline diamond (PCD) and chemical vapor deposition (CVD) diamond cutting tools were used for the milling work. The cutting performance of the two kinds of tools in high-speed milling of SiCf/SiC composites was studied. Tool failure modes and mechanisms were analyzed. The effects of the cooling approach on tool wear and machined surface quality were also investigated. The experimental results showed that under identical cutting parameters and cooling approaches, the PCD tool yielded better cutting performance in terms of a longer tool life and better surface quality than that of the CVD diamond tool. In dry machining, the failure modes of the CVD diamond tool were a large area of spalling on the rake face, edge chipping and severe tool nose fracture, whereas for the PCD tool, only a small area of spalling around the tool nose took place. Compared to the dry machining, the wear magnitudes of both PCD and CVD diamond tools were decreased in cryogenic machining. Additionally, the surface quality also showed significant improvements. This study indicates that the PCD tool is highly suitable for machining of SiCf/SiC composite, and that the cryogenic method can improve machining efficiency and surface quality.
Application of Principal Component Analysis Approach to Predict Shear Strength of Reinforced Concrete Beams with Stirrups
Authors: Koo Seungbum , Shin Dongik , Kim Changhyuk
Published: June 2021

The reinforced concrete (RC) member’s shear strength estimation has been experimentally studied in most cases due to its nonlinear behavior. Many empirical equations have been derived from the experimental data; however, even those adopted in the construction codes do not thoroughly and accurately describe their shear behavior. Theoretically explained equations, on the other hand, are aligned with the experiment; however, they are complicated to use in practice. As shear behavior research is data-driven, the machine learning technique is applicable. Herein, an artificial neural network (ANN) algorithm is trained with 776 experiment results collected from available publications. The raw data is preprocessed by principal component analysis (PCA) before the application of the ANN technique. The predictions of the trained algorithm using ANN with PCA are compared to those of formulae adopted in a few existing building codes. Finally, a parametric study is conducted, and the significance of each variable to the strength of RC members is analyzed.
Polyurethane Composite Foams Synthesized Using Bio-Polyols and Cellulose Filler
Authors: Uram Katarzyna , Leszczyńska Milena , Prociak Aleksander , Czajka Anna , Gloc Michał , Leszczyński Michał K. , Michałowski Sławomir , Ryszkowska Joanna
Published: June 2021

Rigid polyurethane foams were obtained using two types of renewable raw materials: bio-polyols and a cellulose filler (ARBOCEL® P 4000 X, JRS Rettenmaier, Rosenberg, Germany). A polyurethane system containing 40 wt.% of rapeseed oil-based polyols was modified with the cellulose filler in amounts of 1, 2, and 3 php (per hundred polyols). The cellulose was incorporated into the polyol premix as filler dispersion in a petrochemical polyol made using calenders. The cellulose filler was examined in terms of the degree of crystallinity using the powder X-ray diffraction PXRD -and the presence of bonds by means of the fourier transform infrared spectroscopy FT-IR. It was found that the addition of the cellulose filler increased the number of cells in the foams in both cross-sections—parallel and perpendicular to the direction of the foam growth—while reducing the sizes of those cells. Additionally, the foams had closed cell contents of more than 90% and initial thermal conductivity coefficients of 24.8 mW/m∙K. The insulation materials were dimensionally stable, especially at temperatures close to 0 °C, which qualifies them for use as insulation at low temperatures.
Feasibility Study of Fluidic Sealing in Turbine Shroud
Authors: Wasilczuk Filip , Flaszynski Pawel , Pyclik Lukasz , Marugi Krzysztof
Published: June 2021

This paper analyses the methods for manufacturing turbine blades, focusing on the possibility of manufacturing slots in the region of the shroud. The reason for this analysis is the new flow control technique that can be used to limit the shroud leakage flow in a turbine—the air curtain. The air curtain uses a bypass slot to connect the upstream cavern of a shroud seal with the tip of a shroud fin. The bypass slot is an essential part of the solution, while at the same time introducing difficulties in the manufacturing process. Additionally, a parametric study on the bypass slot dimensions is performed using numerical simulations. The features of the numerical model and its validation against experimental data are presented. The parametric study includes the inlet and outlet dimensions, as well as the width of the slot. The most effective dimensions are shown, along with a possible explanation as to why they are the most effective. Interestingly, a slot that does not cover the whole span of the fin is more effective than a slot covering the whole span of the fin. This is caused by additional streamwise vortices that are created in the proximity of the bypass slot.
The Cover Depth Effect on Corrosion-Induced Deterioration of Reinforced Concrete Focusing on Water Penetration: Field Survey and Laboratory Study
Authors: Asamoto Shingo , Sato Junya , Okazaki Shinichiro , Chun Pang-jo , Sahamitmongkol Raktipong , Nguyen Giang Hoang
Published: June 2021

Reinforced concrete bridges were visually surveyed in Japan, Thailand, and Vietnam to study the deterioration caused by internal steel corrosion under different climates, focusing on the concrete cover depth. Spalling or cracking arising from corrosion is likely where water is supplied. According to prior studies and our surveys, a concrete cover depth of more than 40 mm was found to prevent spalling, regardless of environmental conditions and structure age. Because water supply at steel is a key corrosion factor, it was hypothesised that under natural conditions, the water penetration in concrete would remain at a depth of approximately 40 mm. Our laboratory study examined water penetration under drying and wetting conditions. The results also suggested that under periodic rainfall conditions, the threshold of water penetration was not exceeded. The numerical study indicated maximum moisture evaporation to facilitate oxygen diffusion occurred at a depth of approximately 30–40 mm unless the concrete was exposed to continuous drying for more than one month. It was experimentally and numerically concluded that an adequate cover depth of greater than 40 mm could inhibit moisture and oxygen penetration at the steel, which supported the survey findings of cover depth effect on a high resistance to corrosion-induced deterioration despite an increase in service life.
Predictive Model for the Surface Tension Changes of Chemical Solutions Used in a Clean-in-Place System
Authors: Piepiórka-Stepuk Joanna , Sterczyńska Monika , Kalak Tomasz , Jakubowski Marek
Published: June 2021

The paper presents the results concerning the influence of concentration and storage time on the equilibrium surface tension of chemical solutions used in a clean-in place (CIP) system. Standard cleaning solutions (prepared under laboratory conditions) and industrial solutions (used in a CIP system in a brewery) were subjected to tests. Solutions from the brewery were collected after being regenerated and changes in equilibrium surface tension were studied during a three-month storage. In the statistical analysis of the solutions, standard deviations were determined in relation to the averages, and a Tukey’s multiple comparison test was performed to determine the effect of dependent variables on the surface tension of solutions. From the results, a nonlinear regression model was developed that provided a mathematical description of the kinetics of changes in the wetting properties of the solutions during their storage. A linear–logarithmic function was adopted to describe the regeneration. Numerical calculations were performed based on the nonlinear least squares method using the Gauss–Newton algorithm. The adequacy of the regression models with respect to the empirical data was verified by the coefficient of determination R and the standard error of estimation Se. The results showed that as the concentration of the substance in the cleaning solution increased, its wetting properties decreased. The same effect was observed with increased storage time as the greatest changes occurred during the first eight weeks. The study also showed that the use of substances to stabilize the cleaning solutions prevented deterioration of their wetting properties, regardless of the concentration of the active substance or storage time.
Impact of Design Parameters on the Ratio of Compressive to Split Tensile Strength of Self-Compacting Concrete with Recycled Aggregate
Authors: Martínez-García Rebeca , Jagadesh P. , Búrdalo-Salcedo Gabriel , Palencia Covadonga , Fernández-Raga María , Fraile-Fernández Fernando J.
Published: June 2021

Most concrete studies are concentrated on mechanical properties especially strength properties either directly or indirectly (fresh and durability properties). Hence, the ratio of split tensile strength to compressive strength plays a vital role in defining the concrete properties. In this review, the impact of design parameters on the strength ratio of various grades of Self-Compacting Concrete (SCC) with recycled aggregate is assessed. The design parameters considered for the study are Water to Cement (W/C) ratio, Water to Binder (W/B) ratio, Total Aggregates to Cement (TA/C) ratio, Fine Aggregate to Coarse Aggregate (FA/CA) ratio, Water to Solid (W/S) ratio in percentage, superplasticizer (SP) content (kg/cu.m), replacement percentage of recycled coarse aggregates (RCA), replacement percentage of recycled fine aggregates (RFA), fresh density and loading area of the specimen. It is observed that the strength ratio of SCC with recycled aggregates is affected by design parameters.