bluuebunny/crossref_metadata_2025 huggingface dataset:
Hypoxic Conditions Promote the Angiogenic Potential of Human Induced Pluripotent Stem Cell-Derived Extracellular Vesicles
Authors: Andrade André Cronemberger , Wolf Martin , Binder Heide-Marie , Gomes Fausto Gueths , Manstein Felix , Ebner-Peking Patricia , Poupardin Rodolphe , Zweigerdt Robert , Schallmoser Katharina , Strunk Dirk
Published: April 2021

Stem cells secrete paracrine factors including extracellular vesicles (EVs) which can mediate cellular communication and support the regeneration of injured tissues. Reduced oxygen (hypoxia) as a key regulator in development and regeneration may influence cellular communication via EVs. We asked whether hypoxic conditioning during human induced pluripotent stem cell (iPSC) culture effects their EV quantity, quality or EV-based angiogenic potential. We produced iPSC-EVs from large-scale culture-conditioned media at 1%, 5% and 18% air oxygen using tangential flow filtration (TFF), with or without subsequent concentration by ultracentrifugation (TUCF). EVs were quantified by tunable resistive pulse sensing (TRPS), characterized according to MISEV2018 guidelines, and analyzed for angiogenic potential. We observed superior EV recovery by TFF compared to TUCF. We confirmed hypoxia efficacy by HIF-1α stabilization and pimonidazole hypoxyprobe. EV quantity did not differ significantly at different oxygen conditions. Significantly elevated angiogenic potential was observed for iPSC-EVs derived from 1% oxygen culture by TFF or TUCF as compared to EVs obtained at higher oxygen or the corresponding EV-depleted soluble factor fractions. Data thus demonstrate that cell-culture oxygen conditions and mode of EV preparation affect iPSC-EV function. We conclude that selecting appropriate protocols will further improve production of particularly potent iPSC-EV-based therapeutics.
Room-Temperature Structure of Xylitol-Bound Glucose Isomerase by Serial Crystallography: Xylitol Binding in the M1 Site Induces Release of Metal Bound in the M2 Site
Authors: Nam Ki Hyun
Published: April 2021

Glucose isomerase (GI) is an important enzyme that is widely used in industrial applications, such as in the production of high-fructose corn syrup or bioethanol. Studying inhibitor effects on GI is important to deciphering GI-specific molecular functions, as well as potential industrial applications. Analysis of the existing xylitol-bound GI structure revealed low metal occupancy at the M2 site; however, it remains unknown why this phenomenon occurs. This study reports the room-temperature structures of native and xylitol-bound GI from Streptomyces rubiginosus (SruGI) determined by serial millisecond crystallography. The M1 site of native SruGI exhibits distorted octahedral coordination; however, xylitol binding results in the M1 site exhibit geometrically stable octahedral coordination. This change results in the rearrangement of metal-binding residues for the M1 and M2 sites, the latter of which previously displayed distorted metal coordination, resulting in unstable coordination of Mg2+ at the M2 site and possibly explaining the inducement of low metal-binding affinity. These results enhance the understanding of the configuration of the xylitol-bound state of SruGI and provide insights into its future industrial application.
Therapeutic Efficacy of a Novel Acetylated Tetrapeptide in Animal Models of Age-Related Macular Degeneration
Authors: Koo Hye Cheong , Baek Yi-Yong , Choi Jun-Sup , Kim Young-Myeong , Sung Bokyung , Kim Min-Jung , Kim Jae Gyu , You Ji Chang
Published: April 2021

It has been shown previously that a novel tetrapeptide, Arg-Leu-Tyr-Glu (RLYE), derived from human plasminogen inhibits vascular endothelial growth factor (VEGF)-induced angiogenesis, suppresses choroidal neovascularization in mice by an inhibition of VEGF receptor-2 (VEGFR-2) specific signaling pathway. In this study, we report that a modified tetrapeptide (Ac-RLYE) showed improved anti-choroidal neovascularization (CNV) efficacy in a number of animal models of neovascular age-related macular degeneration (AMD) which include rat, rabbit, and minipig. The preventive and therapeutic in vivo efficacy of Ac-RLYE via following intravitreal administration was determined to be either similar or superior to that of ranibizumab and aflibercept. Assessment of the intraocular pharmacokinetic and toxicokinetic properties of Ac-RLYE in rabbits demonstrated that it rapidly reached the retina with minimal systemic exposure after a single intravitreal dose, and it did not accumulate in plasma during repetitive dosing (bi-weekly for 14 weeks). Our results suggested that Ac-RLYE has a great potential for an alternative therapeutics for neovascular (wet) AMD. Since the amino acids in human VEGFR-2 targeted by Ac-RLYE are conserved among the animals employed in this study, the therapeutic efficacies of Ac-RLYE evaluated in those animals are predicted to be observed in human patients suffering from retinal degenerative diseases.
Prolyl 3-Hydroxylase 2 Is a Molecular Player of Angiogenesis
Authors: Pignata Paola , Apicella Ivana , Cicatiello Valeria , Puglisi Caterina , Magliacane Trotta Sara , Sanges Remo , Tarallo Valeria , De Falco Sandro
Published: April 2021

Prolyl 3-hydroxylase 2 (P3H2) catalyzes the post-translational formation of 3-hydroxyproline on collagens, mainly on type IV. Its activity has never been directly associated to angiogenesis. Here, we identified P3H2 gene through a deep-sequencing transcriptome analysis of human umbilical vein endothelial cells (HUVECs) stimulated with vascular endothelial growth factor A (VEGF-A). Differently from many previous studies we carried out the stimulation not on starved HUVECs, but on cells grown to maintain the best condition for their in vitro survival and propagation. We showed that P3H2 is induced by VEGF-A in two primary human endothelial cell lines and that its transcription is modulated by VEGF-A/VEGF receptor 2 (VEGFR-2) signaling pathway through p38 mitogen-activated protein kinase (MAPK). Then, we demonstrated that P3H2, through its activity on type IV Collagen, is essential for angiogenesis properties of endothelial cells in vitro by performing experiments of gain- and loss-of-function. Immunofluorescence studies showed that the overexpression of P3H2 induced a more condensed status of Collagen IV, accompanied by an alignment of the cells along the Collagen IV bundles, so towards an evident pro-angiogenic status. Finally, we found that P3H2 knockdown prevents pathological angiogenesis in vivo, in the model of laser-induced choroid neovascularization. Together these findings reveal that P3H2 is a new molecular player involved in new vessels formation and could be considered as a potential target for anti-angiogenesis therapy.
Nonalcoholic Fatty Liver Disease: Focus on New Biomarkers and Lifestyle Interventions
Authors: Notarnicola Maria , Osella Alberto Ruben , Caruso Maria Gabriella , Pesole Pasqua Letizia , Lippolis Antonio , Tutino Valeria , Bonfiglio Caterina , De Nunzio Valentina , Scavo Maria Principia , Mirizzi Antonella , Franco Isabella , Lippolis Tamara , D’Alessandro Rosalba , Refolo Maria Grazia , Messa Caterina
Published: April 2021

Nonalcoholic fatty liver disease (NAFLD) is considered a hepatic manifestation of metabolic syndrome, characterized from pathological changes in lipid and carbohydrate metabolism. Its main characteristics are excessive lipid accumulation and oxidative stress, which create a lipotoxic environment in hepatocytes leading to liver injury. Recently, many studies have focused on the identification of the genetic and epigenetic modifications that also contribute to NAFLD pathogenesis and their prognostic implications. The present review is aimed to discuss on cellular and metabolic alterations associated with NAFLD, which can be helpful to identify new noninvasive biomarkers. The identification of accumulated lipids in the cell membranes, as well as circulating cytokeratins and exosomes, provides new insights in understanding of NAFLD. This review also suggests that lifestyle modifications remain the main prevention and/or treatment for NAFLD.
Extracytoplasmic Function σ Factors as Tools for Coordinating Stress Responses
Authors: de Dios Rubén , Santero Eduardo , Reyes-Ramírez Francisca
Published: April 2021

The ability of bacterial core RNA polymerase (RNAP) to interact with different σ factors, thereby forming a variety of holoenzymes with different specificities, represents a powerful tool to coordinately reprogram gene expression. Extracytoplasmic function σ factors (ECFs), which are the largest and most diverse family of alternative σ factors, frequently participate in stress responses. The classification of ECFs in 157 different groups according to their phylogenetic relationships and genomic context has revealed their diversity. Here, we have clustered 55 ECF groups with experimentally studied representatives into two broad classes of stress responses. The remaining 102 groups still lack any mechanistic or functional insight, representing a myriad of systems yet to explore. In this work, we review the main features of ECFs and discuss the different mechanisms controlling their production and activity, and how they lead to a functional stress response. Finally, we focus in more detail on two well-characterized ECFs, for which the mechanisms to detect and respond to stress are complex and completely different: Escherichia coli RpoE, which is the best characterized ECF and whose structural and functional studies have provided key insights into the transcription initiation by ECF-RNAP holoenzymes, and the ECF15-type EcfG, the master regulator of the general stress response in Alphaproteobacteria.
Bioprinting Via a Dual-Gel Bioink Based on Poly(Vinyl Alcohol) and Solubilized Extracellular Matrix towards Cartilage Engineering
Authors: Setayeshmehr Mohsen , Hafeez Shahzad , van Blitterswijk Clemens , Moroni Lorenzo , Mota Carlos , Baker Matthew B.
Published: April 2021

Various hydrogel systems have been developed as biomaterial inks for bioprinting, including natural and synthetic polymers. However, the available biomaterial inks, which allow printability, cell viability, and user-defined customization, remains limited. Incorporation of biological extracellular matrix materials into tunable synthetic polymers can merge the benefits of both systems towards versatile materials for biofabrication. The aim of this study was to develop novel, cell compatible dual-component biomaterial inks and bioinks based on poly(vinyl alcohol) (PVA) and solubilized decellularized cartilage matrix (SDCM) hydrogels that can be utilized for cartilage bioprinting. In a first approach, PVA was modified with amine groups (PVA-A), and mixed with SDCM. The printability of the PVA-A/SDCM formulations cross-linked by genipin was evaluated. On the second approach, the PVA was functionalized with cis-5-norbornene-endo-2,3-dicarboxylic anhydride (PVA-Nb) to allow an ultrafast light-curing thiol-ene cross-linking. Comprehensive experiments were conducted to evaluate the influence of the SDCM ratio in mechanical properties, water uptake, swelling, cell viability, and printability of the PVA-based formulations. The studies performed with the PVA-A/SDCM formulations cross-linked by genipin showed printability, but poor shape retention due to slow cross-linking kinetics. On the other hand, the PVA-Nb/SDCM showed good printability. The results showed that incorporation of SDCM into PVA-Nb reduces the compression modulus, enhance cell viability, and bioprintability and modulate the swelling ratio of the resulted hydrogels. Results indicated that PVA-Nb hydrogels containing SDCM could be considered as versatile bioinks for cartilage bioprinting.
Pregnancy-Related Extracellular Vesicles Revisited
Authors: Condrat Carmen Elena , Varlas Valentin Nicolae , Duică Florentina , Antoniadis Panagiotis , Danila Cezara Alina , Cretoiu Dragos , Suciu Nicolae , Crețoiu Sanda Maria , Voinea Silviu Cristian
Published: April 2021

Extracellular vesicles (EVs) are small vesicles ranging from 20–200 nm to 10 μm in diameter that are discharged and taken in by many different types of cells. Depending on the nature and quantity of their content—which generally includes proteins, lipids as well as microRNAs (miRNAs), messenger-RNA (mRNA), and DNA—these particles can bring about functional modifications in the receiving cells. During pregnancy, placenta and/or fetal-derived EVs have recently been isolated, eliciting interest in discovering their clinical significance. To date, various studies have associated variations in the circulating levels of maternal and fetal EVs and their contents, with complications including gestational diabetes and preeclampsia, ultimately leading to adverse pregnancy outcomes. Furthermore, EVs have also been identified as messengers and important players in viral infections during pregnancy, as well as in various congenital malformations. Their presence can be detected in the maternal blood from the first trimester and their level increases towards term, thus acting as liquid biopsies that give invaluable insight into the status of the feto-placental unit. However, their exact roles in the metabolic and vascular adaptations associated with physiological and pathological pregnancy is still under investigation. Analyzing peer-reviewed journal articles available in online databases, the purpose of this review is to synthesize current knowledge regarding the utility of quantification of pregnancy related EVs in general and placental EVs in particular as non-invasive evidence of placental dysfunction and adverse pregnancy outcomes, and to develop the current understanding of these particles and their applicability in clinical practice.
Metal–Organic Frameworks as Versatile Platforms for Organometallic Chemistry
Authors: Chen Fan , Drake Hannah F. , Feng Liang , Powell Joshua A. , Wang Kun-Yu , Yan Tian-Hao , Zhou Hong-Cai
Published: April 2021

Metal–organic frameworks (MOFs) are emerging porous materials with highly tunable structures developed in the 1990s, while organometallic chemistry is of fundamental importance for catalytic transformation in the academic and industrial world for many decades. Through the years, organometallic chemistry has been incorporated into functional MOF construction for diverse applications. Here, we will focus on how organometallic chemistry is applied in MOF design and modifications from linker-centric and metal-cluster-centric perspectives, respectively. Through structural design, MOFs can function as a tailorable platform for traditional organometallic transformations, including reaction of alkenes, cross-coupling reactions, and C–H activations. Besides, an overview will be made on other application categories of organometallic MOFs, such as gas adsorption, magnetism, quantum computing, and therapeutics.
Persistent Ventricle Partitioning in the Adult Zebrafish Heart
Authors: Pfefferli Catherine , Moran Hannah R. , Felker Anastasia , Mosimann Christian , Jaźwińska Anna
Published: April 2021

The vertebrate heart integrates cells from the early-differentiating first heart field (FHF) and the later-differentiating second heart field (SHF), both emerging from the lateral plate mesoderm. In mammals, this process forms the basis for the development of the left and right ventricle chambers and subsequent chamber septation. The single ventricle-forming zebrafish heart also integrates FHF and SHF lineages during embryogenesis, yet the contributions of these two myocardial lineages to the adult zebrafish heart remain incompletely understood. Here, we characterize the myocardial labeling of FHF descendants in both the developing and adult zebrafish ventricle. Expanding previous findings, late gastrulation-stage labeling using drl-driven CreERT2 recombinase with a myocardium-specific, myl7-controlled, loxP reporter results in the predominant labeling of FHF-derived outer curvature and the right side of the embryonic ventricle. Raised to adulthood, such lineage-labeled hearts retain broad areas of FHF cardiomyocytes in a region of the ventricle that is positioned at the opposite side to the atrium and encompasses the apex. Our data add to the increasing evidence for a persisting cell-based compartmentalization of the adult zebrafish ventricle even in the absence of any physical boundary.
Cryptococcus neoformans and Cryptococcus gattii Species Complexes in Latin America: A Map of Molecular Types, Genotypic Diversity, and Antifungal Susceptibility as Reported by the Latin American Cryptococcal Study Group
Authors: Firacative Carolina , Meyer Wieland , Castañeda Elizabeth
Published: April 2021

Cryptococcosis, a potentially fatal mycosis, is caused by members of the Cryptococcus neoformans and Cryptococcus gattii species complexes. In Latin America, cryptococcal meningitis is still an important health threat with a significant clinical burden. Analysis of publicly available molecular data from 5686 clinical, environmental, and veterinary cryptococcal isolates from member countries of the Latin American Cryptococcal Study Group showed that, as worldwide, C. neoformans molecular type VNI is the most common cause of cryptococcosis (76.01%) in HIV-infected people, followed by C. gattii molecular type VGII (12.37%), affecting mostly otherwise healthy hosts. These two molecular types also predominate in the environment (68.60% for VNI and 20.70% for VGII). Among the scarce number of veterinary cases, VGII is the predominant molecular type (73.68%). Multilocus sequence typing analysis showed that, in Latin America, the C. neoformans population is less diverse than the C. gattii population (D of 0.7104 vs. 0.9755). Analysis of antifungal susceptibility data showed the presence of non-wild-type VNI, VGI, VGII, and VGIII isolates in the region. Overall, the data presented herein summarize the progress that has been made towards the molecular epidemiology of cryptococcal isolates in Latin America, contributing to the characterization of the genetic diversity and antifungal susceptibility of these globally spreading pathogenic yeasts.
Weeds as Pathogen Hosts and Disease Risk for Crops in the Wake of a Reduced Use of Herbicides: Evidence from Yam (Dioscorea alata) Fields and Colletotrichum Pathogens in the Tropics
Authors: Dentika Pauline , Ozier-Lafontaine Harry , Penet Laurent
Published: April 2021

The transition toward sustainable agriculture requires rethinking cropping systems in the light of less intensive and chemically reliant practices. Weed management is one of the target practices to evolve cropping systems with decreased impact on the environment. While softened management will lead to increased weeds/crops coexistence, it is of importance to assess the relative benefits and drawbacks of new practices. Among the potential drawbacks of weeds/crops coexistence, disease risk may increase if weeds are hosting pathogens. In this study, we assessed the potential of weeds for hosting pathogenic generalist fungi known to translate into disease in crops. We first describe prevalence in fields after harvest and relate prevalence to species characteristics and communities. Then, we directly test the idea that weeds serve as inoculums sources during cropping with a natural experiment. This study highlights variation in host skill among feral weeds for Colletotrichum species, including potential congeneric sub-specialization on different weeds within communities. Last, prevalence within fields was more correlated to focal crop inoculation rates compared to local weed load, but there was a significant correlation effect with prevalence on weeds in the vicinity of fields, suggesting that weeds are mediating disease levels at the local scale, too. Results pointed to the importance of weed host skill in disease risk yet open the door to the potential control of pathogens via targeted weed management.
Valorization of Lignocellulosic Wastes to Produce Phytase and Cellulolytic Enzymes from a Thermophilic Fungus, Thermoascus aurantiacus SL16W, under Semi-Solid State Fermentation
Authors: Tanruean Keerati , Penkhrue Watsana , Kumla Jaturong , Suwannarach Nakarin , Lumyong Saisamorn
Published: April 2021

Agricultural wastes are lignocellulosic biomasses that contain high mineral and nutrient contents. This waste can be used as a raw material in industrial enzyme production by microbial fermentation. Phytase is an important enzyme used in animal feed to enhance the amount of phosphorus available for the growth and overall health improvement of monogastric animals. Fungi offer high potential as an effective source in the production of various extracellular enzymes. In this study, the production of lignocellulolytic enzymes (endoglucanase and xylanase) and phytase by a thermophilic fungus, namely Thermoascus aurantiacus strain SL16W, was evaluated using sixteen different Thai agricultural forms of waste under conditions of high temperature (45 °C). Semi-solid state fermentation was used in the production experiments. The results of this study reveal that the highest phytase activity (58.6 U/g substrate) was found in rice bran, whereas the highest degrees of activity of endoglucanase and xylanase were observed in wheat bran and red tea leaves at 19 and 162 U/g substrate, respectively. Consequently, the optimal conditions for phytase production of this fungus using rice bran were investigated. The results indicate that the highest phytase yield (58.6 to 84.1 U/g substrate) was observed in rice bran containing 0.5% ammonium sulfate as a nitrogen source with 10 discs of inoculum size at a cultivation period of 9 days at 45 °C and moisture content of 95%. Notably, the phytase yield increased by 1.71-fold, while endoglucanase and xylanase were also increased by 1.69- and 1.12-fold, respectively. Furthermore, the crude enzyme obtained from the optimal condition was extracted. The crude enzyme extract was then separately added to red tea leaves, rice straw, corncobs, palm residue, and peanut husks. Subsequently, total reducing sugar and phosphorus contents were determined. The results indicate that the highest level of reducing sugar (122.6 mg/L) and phosphorus content (452.6 mg/L) (p < 0.05) were obtained in palm residue at 36 and 48 h, respectively, after the addition of the crude enzyme extract. This study has provided valuable information on a potentially eco-friendly way to valorize agricultural waste into value-added products as industrial enzymes.
Clusters of Skeptical Consumers Based on Technology and AI Acceptance, Perception of Social Media Information and Celebrity Trend Setter
Authors: Pelau Corina , Pop Mihai-Ionut , Ene Irina , Lazar Laura
Published: April 2021

The present consumer is surrounded every day by a huge amount of data and information and is confronted with the need to process the received information. Based on the existing content and the development of user generated content and fake news, consumers develop more and more a skeptical opinion regarding existing media information. In this paper we determine four clusters of consumers based on technology and artificial intelligence (AI) acceptance, skeptical opinion regarding media information, need for validation of received information and the influence of celebrity trend setters. For each of the clusters, we analyze the relationship between the skeptical opinion of consumers related to social media information and some present trends about the development of technologies and AI, the influence of celebrity trend setters and the need to check the received information. The results of the research show that the development of technologies and AI have an influence on the skeptical opinion related to media information for some consumer groups. The celebrity trend setter has a significant influence on the skeptical opinion only for one of the consumer groups. The need for information and news validation is related to the skeptical opinion regarding media information, but in different ways for the determined clusters.
Performance Test and Microstructure of Modified PVC Aggregate-Hybrid Fiber Reinforced Engineering Cementitious Composite (ECC)
Authors: Hu Shi , Cai Haibing , Hong Rongbao , Li Mengkai , Yao Fangxing
Published: April 2021

This study aims to solve the problems of the high cost, heavy pollution and poor performance of traditional engineered cementitious composites (ECC) by adding modified Polyvinyl chloride (PVC) aggregate, Polypropylene (PP)–Polyvinyl alcohol (PVA) hybrid fiber and large amount of fly ash. The PVC aggregate is modified by pre-coating silica fume with a PP fiber volume content of 0.5%, PVA fiber volume contents of 1%, 1.5%, and 2%, PVC aggregate contents of 10%, 20%, and 30%, and fly ash volume content of 69%. Different properties and microstructures were studied by carrying out cube compression tests, splitting tensile tests, water absorption tests, drop hammer impact tests, scanning electron microscopy and nuclear magnetic resonance tests. According to the test results, under the same content of PVC aggregate, the use of modified PVC aggregate can, not only effectively avoid the decrease in strength and increase of water absorption, but also improve brittleness and impact failure energy. Regardless of the kind and content of fiber, the compressive strength and brittleness will decrease, while the splitting tensile strength, water absorption, and impact failure energy will increase. After adding 0.5% PP and 1.5% PVA fiber, the performance is ordinary and a negative mixing effect occurs. As more modified PVC aggregate is added, the strength of the ECC concrete with PP–PVA hybrid fiber and modified PVC aggregate added slowly decrease, while the water absorption and impact failure energy increase. Based on a comprehensive analysis of the test data, the reinforcement method of adding 1.5% PVA-0.5% PP hybrid fiber-30% modified PVC aggregate is superior to adding 1.5% PVA fiber, but slightly inferior to adding 2% PVA fiber. This study argues that the reinforcement method is of great significance for the promotion and application of ECC.
The Effect of Crystalline Waterproofing Admixtures on the Self-Healing and Permeability of Concrete
Authors: Gojević Anita , Ducman Vilma , Netinger Grubeša Ivanka , Baričević Ana , Banjad Pečur Ivana
Published: April 2021

This paper investigates the effectiveness of a specific crystalline waterproofing admixture (CWA) in concrete as a function of a water–binder ratio. Four concrete mixes with and without CWA were prepared; two of them with a water–binder ratio of 0.45 and two of them with a water–binder ratio of 0.55. Water permeability and compressive strength were tested on hardened concrete specimens and self-healing of cracks over time was observed. Cement paste and CWA paste were prepared to clarify the results obtained on the concrete specimens. SEM and EDS and XRD and FTIR were performed on the hardened pastes to explain the mechanism of CWA working. The results show that the addition of CWA had no significant effect on the compressive strength of the concrete, but reduced the water penetration depth in the concrete, and the reduction was more effective for mixes with lower water–binder ratio. Regarding the self-healing effect, it can be concluded that the addition of CWA improves the crack healing in concrete, but the efficiency of self-healing is highly dependent on the initial crack width. The mechanisms involved in the reduction of water penetration depth and crack healing in concrete can be explained by different mechanisms; one is creation of the CSH gel from unreacted clinker grains, then formation carbonate, and additional mechanism is gel formation (highly expansive Mg-rich hydro-carbonate) from magnesium based additives. The presence of sodium silicate, which would transform into carbonate/bicarbonate, also cannot be excluded.
Impact of Zinc- or Copper-Doped Mesoporous Bioactive Glass Nanoparticles on the Osteogenic Differentiation and Matrix Formation of Mesenchymal Stromal Cells
Authors: Westhauser Fabian , Decker Simon , Nawaz Qaisar , Rehder Felix , Wilkesmann Sebastian , Moghaddam Arash , Kunisch Elke , Boccaccini Aldo R.
Published: April 2021

Mesoporous bioactive glass nanoparticles (MBGNs) have gained relevance in bone tissue engineering, especially since they can be used as vectors for therapeutically active ions like zinc (Zn) or copper (Cu). In this study, the osteogenic properties of the ionic dissolution products (IDPs) of undoped MBGNs (composition in mol%: 70 SiO2, 30 CaO) and MBGNs doped with 5 mol% of either Zn (5Zn-MBGNs) or Cu (5Cu-MBGNs; compositions in mol%: 70 SiO2, 25 CaO, 5 ZnO/CuO) on human bone marrow-derived mesenchymal stromal cells were evaluated. Extracellular matrix (ECM) formation and calcification were assessed, as well as the IDPs’ influence on viability, cellular osteogenic differentiation and the expression of genes encoding for relevant members of the ECM. The IDPs of undoped MBGNs and 5Zn-MBGNs had a comparable influence on cell viability, while it was enhanced by IDPs of 5Cu-MBGNs compared to the other MBGNs. IDPs of 5Cu-MBGNs had slightly positive effects on ECM formation and calcification. 5Zn-MBGNs provided the most favorable pro-osteogenic properties since they increased not only cellular osteogenic differentiation and ECM-related gene expression but also ECM formation and calcification significantly. Future studies should analyze other relevant properties of MBGNs, such as their impact on angiogenesis.
Grain-to-Grain Interaction Effect in Polycrystalline Plain Low-Carbon Steel within Elastic Deformation Region
Authors: Qiu Hai , Ueji Rintaro , Kimura Yuuji , Inoue Tadanobu
Published: April 2021

A grain is surrounded by grains with different crystal orientations in polycrystalline plain low-carbon steel. The grain is constrained by its adjacent grains in the tension process. The interaction of the grain with the adjacent grains was investigated within the elastic deformation region. The following results have been obtained: (1) the Young’s modulus of a grain without consideration of grain-to-grain interaction is denoted as the inherent Young’s modulus; when the inherent Young’s modulus of a grain is equal to the Young’s modulus of the bulk material, there is almost no interaction between the grain and its adjacent grains; when a grain has a great difference between its inherent Young’s modulus and the Young’s modulus of the bulk material, its grain-to-grain interactions increase significantly; (2) the grain-to-grain interaction is mainly caused by the difference in the inherent Young’s modulus between the grain and its adjacent grains; the misorientation angle between the grain and its adjacent grains has almost no effect on the grain-to-grain interaction.
Re-Melting Behaviour and Wear Resistance of Vanadium Carbide Precipitating Cr27.5Co14Fe22Mo22Ni11.65V2.85 High Entropy Alloy
Authors: Treutler Kai , Lorenz Swenja , Wesling Volker
Published: April 2021

High entropy alloys (HEAs) are among of the most promising new metal material groups. The achievable properties can exceed those of common alloys in different ways. Due to the mixture of five or more alloying elements, the variety of high entropy alloys is fairly huge. The presented work will focus on some first insights on the weldability and the wear behavior of vanadium carbide precipitation Cr27.5Co14Fe22Mo22Ni11.65V2.85 HEA. The weldability should always be addressed in an early stage of any alloy design to avoid welding-related problems afterwards. The cast Cr27.5Co14Fe22Mo22Ni11.65V2.85 HEA has been remelted using a TIG welding process and the resulting microstructure has been examined. The changes in the microstructure due to the remelting process showed little influence of the welding process and no welding-related problems like hot cracks have been observed. It will be shown that vanadium carbides or vanadium-rich phases precipitate after casting and remelting in a two phased HEA matrix. The hardness of the as cast alloy is 324HV0.2 and after remelting the hardness rises to 339HV0.2. The wear behavior can be considered as comparable to a Stellite 6 cobalt base alloy as determined in an ASTM G75 test. Overall, the basic HEA design is promising due to the precipitation of vanadium carbides and should be further investigated.
The Role of Anisotropy in Distinguishing Domination of Néel or Brownian Relaxation Contribution to Magnetic Inductive Heating: Orientations for Biomedical Applications
Authors: Nguyen Luu , Phong Pham , Nam Pham , Manh Do , Thanh Nguyen , Tung Le , Phuc Nguyen
Published: April 2021

Magnetic inductive heating (MIH) has been a topic of great interest because of its potential applications, especially in biomedicine. In this paper, the parameters characteristic for magnetic inductive heating power including maximum specific loss power (SLPmax), optimal nanoparticle diameter (Dc) and its width (ΔDc) are considered as being dependent on magnetic nanoparticle anisotropy (K). The calculated results suggest 3 different Néel-domination (N), overlapped Néel/Brownian (NB), and Brownian-domination (B) regions. The transition from NB- to B-region changes abruptly around critical anisotropy Kc. For magnetic nanoparticles with low K (K < Kc), the feature of SLP peaks is determined by a high value of Dc and small ΔDc while those of the high K (K > Kc) are opposite. The decreases of the SLPmax when increasing polydispersity and viscosity are characterized by different rates of d(SLPmax)/dσ and d(SLPmax)/dη depending on each domination region. The critical anisotropy Kc varies with the frequency of an alternating magnetic field. A possibility to improve heating power via increasing anisotropy is analyzed and deduced for Fe3O4 magnetic nanoparticles. For MIH application, the monodispersity requirement for magnetic nanoparticles in the B-region is less stringent, while materials in the N- and/or NB-regions are much more favorable in high viscous media. Experimental results on viscosity dependence of SLP for CoFe2O4 and MnFe2O4 ferrofluids are in good agreement with the calculations. These results indicated that magnetic nanoparticles in the N- and/or NB-regions are in general better for application in elevated viscosity media.
Effect of Graded-Indium-Content Superlattice on the Optical and Structural Properties of Yellow-Emitting InGaN/GaN Quantum Wells
Authors: Li Xuan , Liu Jianping , Su Xujun , Huang Siyi , Tian Aiqin , Zhou Wei , Jiang Lingrong , Ikeda Masao , Yang Hui
Published: April 2021

We have improved the material quality of the high indium composition InGaN/GaN multiple quantum wells (MQWs) grown on free-standing GaN substrates using the graded-indium-content superlattice. We found that by adopting a graded-indium-content superlattice structure, the spectral FWHM of the yellow emitting InGaN/GaN MQW was reduced from 181 meV to 160 meV, and the non-radiative recombination lifetime increased from 13 ns to 44 ns. Besides, the graded-indium-content superlattice can mitigate strain relaxation in high indium composition MQWs as shown by the TEM diffraction patterns.
Pop-In Phenomenon as a Fundamental Plasticity Probed by Nanoindentation Technique
Authors: Ohmura Takahito , Wakeda Masato
Published: April 2021

The attractive strain burst phenomenon, so-called “pop-in”, during indentation-induced deformation at a very small scale is discussed as a fundamental deformation behavior in various materials. The nanoindentation technique can probe a mechanical response to a very low applied load, and the behavior can be mechanically and physically analyzed. The pop-in phenomenon can be understood as incipient plasticity under an indentation load, and dislocation nucleation at a small volume is a major mechanism for the event. Experimental and computational studies of the pop-in phenomenon are reviewed in terms of pioneering discovery, experimental clarification, physical modeling in the thermally activated process, crystal plasticity, effects of pre-existing lattice defects including dislocations, in-solution alloying elements, and grain boundaries, as well as atomistic modeling in computational simulation. The related non-dislocation behaviors are also discussed in a shear transformation zone in bulk metallic glass materials and phase transformation in semiconductors and metals. A future perspective from both engineering and scientific views is finally provided for further interpretation of the mechanical behaviors of materials.
Low Serum Uric Acid Predicts Risk of a Composite Disease Endpoint
Authors: Özpamuk-Karadeniz Fatma , Karadeniz Yusuf , Kaya Adnan , Altay Servet , Can Günay , Onat Altan
Published: April 2021

Background and objectives: Mortality may increase in hypouricemia as well as inhyperuricemia. We assessed the predictive value of low serum uric acid (SUA) levels on the risk of overall mortality or a composite endpoint of death and nonfatal events. Materials and Methods: In 1013 community-based middle-aged adults, free of uncontrolled diabetes and coronary heart disease at baseline, the association of sex-specific SUA tertiles with defined outcomes was evaluated prospectively by logistic regression, stratified to gender and presence of type-2 diabetes, using recent criteria. Results: Totally, 43 deaths and additional incident nonfatal events in 157 cases were recorded at a median 3.4 years’ follow-up. Multivariable linear regression disclosed SUA to be significantly associated among non-diabetic individuals positively with creatinine, triglycerides, and body mass index in women further with fasted glucose. In multivariable-adjusted logistic regression analysis, sex-specifically dichotomized baseline uric acid (<5.1 and <4.1 mg/dL vs. higher values) significantly predicted the non-fatal events in the whole sample (relative risk (RR) 1.51 [95% confidence interval (CI) 1.02; 2.26]), as well as in men, while composite endpoint in the whole sample tended to rise (RR 1.38). Compared with the intermediate one, the top and bottom SUA tertiles combined tended to confer mortality risk (RR 2.40 [95% CI 0.89; 6.51]). Adverse outcomes in diabetic women were predicted by tertiles 2 and 3. Conclusions: Inverse association of SUA with adverse outcomes, especially in men, is consistent with the involvement of uric acid mass in autoimmune activation. The positive association of uric acid with adverse outcomes in diabetic women is likely mediated by concomitant high-density lipoprotein dysfunction.
Graphene Oxide-Based Nanofiltration for Hg Removal from Wastewater: A Mini Review
Authors: Zunita Megawati
Published: April 2021

Mercury (Hg) is one of heavy metals with the highest toxicity and negative impact on the biological functions of living organisms. Therefore, many studies are devoted to solving the problem of Hg separation from wastewater. Membrane-based separation techniques have become more preferable in wastewater treatment area due to their ease of operation, mild conditions and also more resistant to toxic pollutants. This technique is also flexible and has a wide range of possibilities to be integrated with other techniques. Graphene oxide (GO) and derivatives are materials which have a nanostructure can be used as a thin and flexible membrane sheet with high chemical stability and high mechanical strength. In addition, GO-based membrane was used as a barrier for Hg vapor due to its nano-channels and nanopores. The nano-channels of GO membranes were also used to provide ion mobility and molecule filtration properties. Nowadays, this technology especially nanofiltration for Hg removal is massively explored. The aim of the review paper is to investigate Hg removal using functionalized graphene oxide nanofiltration. The main focus is the effectiveness of the Hg separation process.
S-Layer Ultrafiltration Membranes
Authors: Schuster Bernhard , Sleytr Uwe B.
Published: April 2021

Monomolecular arrays of protein subunits forming surface layers (S-layers) are the most common outermost cell envelope components of prokaryotic organisms (bacteria and archaea). Since S-layers are periodic structures, they exhibit identical physicochemical properties for each constituent molecular unit down to the sub-nanometer level. Pores passing through S-layers show identical size and morphology and are in the range of ultrafiltration membranes. The functional groups on the surface and in the pores of the S-layer protein lattice are accessible for chemical modifications and for binding functional molecules in very precise fashion. S-layer ultrafiltration membranes (SUMs) can be produced by depositing S-layer fragments as a coherent (multi)layer on microfiltration membranes. After inter- and intramolecular crosslinking of the composite structure, the chemical and thermal resistance of these membranes was shown to be comparable to polyamide membranes. Chemical modification and/or specific binding of differently sized molecules allow the tuning of the surface properties and molecular sieving characteristics of SUMs. SUMs can be utilized as matrices for the controlled immobilization of functional biomolecules (e.g., ligands, enzymes, antibodies, and antigens) as required for many applications (e.g., biosensors, diagnostics, enzyme- and affinity-membranes). Finally, SUM represent unique supporting structures for stabilizing functional lipid membranes at meso- and macroscopic scale.
Hippocampal Atrophy in Pediatric Transplant Recipients with Human Herpesvirus 6B
Authors: Miyake Misa , Kawamura Yoshiki , Ishihara Naoko , Suzuki Shigetaka , Miura Hiroki , Sakaguchi Yoko , Tanaka Masaharu , Takahashi Yoshiyuki , Kojima Seiji , Toyama Hiroshi , Natsume Jun , Yoshikawa Tetsushi
Published: April 2021

The aim of this study was to determine whether human herpesvirus 6B (HHV-6B) infection can impair the hippocampus in pediatric hematopoietic stem cell transplant (HSCT) recipients. Study subjects were pediatric HSCT recipients monitored for HHV-6B infection who underwent brain MRI before and after transplantation. Volumetric analysis of the hippocampus was performed. Of the 107 patients that received HSCT at Nagoya University Hospital Between July 2008 and April 2014, 20 were eligible for volumetric analysis. Eight patients had HHV-6B infection, of whom two had encephalopathy at the time of HHV-6B infection. None of the 12 patients without HHV-6B infection had encephalopathy. The median ratio of the right hippocampal volume from before to after transplantation was 0.93 in patients with HHV-6B infection and 1.02 in without HHV-6B infection (p = 0.007). The median ratio of the left hippocampal volume ratio in patients with and without HHV-6B infection was 0.92 and 1.00, respectively (p = 0.003). Among the eight patients with HHV-6B infection, four had a marked reduction in hippocampal volume (volume ratio < 0.90). Only one of these patients had neurological symptoms at the time of HHV-6B infection. The reduction in the hippocampal volume ratio was higher in pediatric HSCT recipients with HHV-6B infection than those without viral infection. Neurological follow-up may be required for pediatric HSCT recipients with HHV-6B infection.
European Population of Pectobacterium punjabense: Genomic Diversity, Tuber Maceration Capacity and a Detection Tool for This Rarely Occurring Potato Pathogen
Authors: Cigna Jérémy , Laurent Angélique , Waleron Malgorzata , Waleron Krzysztof , Dewaegeneire Pauline , van der Wolf Jan , Andrivon Didier , Faure Denis , Hélias Valérie
Published: April 2021

Enterobacteria belonging to the Pectobacterium and Dickeya genera are responsible for soft rot and blackleg diseases occurring in many crops around the world. Since 2016, the number of described species has more than doubled. However, some new species, such as Pectobacterium punjabense, are often poorly characterized, and little is known about their genomic and phenotypic variation. Here, we explored several European culture collections and identified seven strains of P. punjabense. All were collected from potato blackleg symptoms, sometimes from a long time ago, i.e., the IFB5596 strain isolated almost 25 years ago. We showed that this species remains rare, with less than 0.24% of P. punjabense strains identified among pectinolytic bacteria present in the surveyed collections. The analysis of the genomic diversity revealed the non-clonal character of P. punjabense species. Furthermore, the strains showed aggressiveness differences. Finally, a qPCR Taqman assay was developed for rapid and specific strain characterization and for use in diagnostic programs.
Seroprevalence and Risk Factors of Brucella Infection in Dairy Animals in Urban and Rural Areas of Bihar and Assam, India
Authors: Deka Ram Pratim , Shome Rajeswari , Dohoo Ian , Magnusson Ulf , Randolph Delia Grace , Lindahl Johanna F.
Published: April 2021

This study assessed seropositivity of Brucella infection in dairy animals and risk factors associated with it. The cross-sectional study used multi-stage, random sampling in the states of Bihar and Assam in India. In total, 740 dairy animals belonging to 534 households of 52 villages were covered under this study. Serological testing was conducted by indirect enzyme-linked immunosorbent assay (iELISA). Animal-level Brucella seropositivity was found to be 15.9% in Assam and 0.3% in Bihar. Seropositivity in urban areas (18.7%) of Assam was found to be higher than in rural areas (12.4%). Bihar was excluded from the risk factor analysis, as only one Brucella seropositive sample was detected in the state. A total of 30 variables were studied for assessing risk factors, of which 15 were selected for multivariable regression analyses following a systematic process. Finally, only three risk factors were identified as statistically significant. It was found that animals belonging to districts having smaller-sized herds were less likely (p < 0.001) to be Brucella seropositive than animals belonging to districts having larger-sized herds. Furthermore, the chance of being Brucella seropositive increased (p = 0.007) with the increase in age of dairy animals, but decreased (p = 0.072) with the adoption of artificial insemination (AI) for breeding. We speculated that the identified risk factors in Assam likely explained the reason behind lower Brucella seropositivity in Bihar, and therefore any future brucellosis control program should focus on addressing these risk factors.
Influence of Strain Rate, Temperature and Chemical Composition on High Silicon Ductile Iron
Authors: Borgström Henrik
Published: April 2021

Today, the use of solution hardened ductile iron is limited by brittleness under certain conditions. If chassis components are subjected to loads having high strain rates exceeding those imposed during tensile testing at sub-zero temperatures, unexpected failure can occur. Therefore, it is the purpose of this review to discuss three main mechanisms, which have been related to brittle failure in high silicon irons: intercritical embrittlement, the integrity of the ferritic matrix and deformation mechanisms in the graphite. Intercritical embrittlement is mainly attributed to the formation of Mg- and S-rich grain boundary films. The formation of these films is suppressed if the amount of free Mg- and MgS-rich inclusions is limited by avoiding excess Mg and/or by the passivation of free Mg with P. If the grain boundary film is not suppressed, the high silicon iron has very low elongations in the shakeout temperature regime: 300 to 500 °C. The integrity and strength of the ferrite are limited by the reduced ordering of the silicumferrite with increasing silicon content, once the “ordinary” ferrite is saturated at 3% silicon, depending on the cooling conditions. Finally, the graphite damaging mechanisms are what dictate the properties most at low temperatures (sub −20 °C).