Search

Complex concentrated alloys (CCAs) with a face-centered-cubic (FCC) structure exhibit remarkable mechanical properties, introducing the expansion of compositional space in alloy design for structural materials. The formation of a single solid-solution phase is enabled by configuring various 3d-transition elements, while doping other elements even of a small portion generally leads to the formation of brittle intermetallic compounds. Herein, we demonstrate through a systematic investigation of single FCC (CoNi)100-xMox alloys that a wide range of refractory element Mo can simultaneously improve the strength and ductility while sustaining the solid-solution structure. The addition of Mo with a larger atomic size than those of 3d-transition elements introduces severe lattice distortion in the FCC lattice and causes grain-boundary segregation enriched by Mo atoms. In addition, increasing Mo content effectively reduces the stacking fault energy (SFE). The increased lattice distortion with Mo content enhances the solid-solution strengthening of the alloys. Besides, along with reduced SFE and stabilization of the dislocation emission site by grain-boundary segregation, this elevated solid-solution strengthening increases grain-boundary strengthening, reaching a yield strength of ∼1 GPa. Moreover, the reduction of SFE with increasing Mo results in the transition of dislocation substructures and the refinement of deformation twins, allowing for enhanced strain-hardening capability and thus ∼1.3 GPa tensile strength and ∼50% ductility. Such compositive and synergetic effects of refractory element Mo enable the CCAs with a single FCC solid solution to overcome the strength and ductility trade-off., Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public., Team Marcel Sluiter

The issue of hydrogen embrittlement (HE) in face-centered (FCC) structured alloys is significant for H storage and transportation application due to unanticipated damage beyond its predicted service life. This unpredictable situation may harm human life and limit hydrogen to a reliable source of renewable energy in industrial fields. Recent research has suggested that multi-principal element alloys possess high resistance to HE. However, there has been limited exploration of how their unique properties affect the HE mechanisms. In this study, using simple model VCrCoNi alloys with analogous grain sizes, the reduction rate of ductility by hydrogen uptake was measured through a slow strain rate tensile test following electro-chemical H charging. Further, the origin of HE resistance was investigated by analyzing various factors such as hydrogen contents, fracture and deformation behaviors, and grain boundary properties using thermal desorption spectroscopy, scanning electron microscope, and electron backscatter diffraction. Despite the consistent trends of the H content, stacking fault energy, and stress with increasing V content, the resistance to HE is the highest for the alloy with an intermediate ratio of V and Cr, namely, for the V0.7Cr0.3CoNi alloy. Through the analysis of grain boundary characteristics, the high resistance is attributed to large fractions of special boundaries and special triple junctions and large twin-related domain size, which suppresses crack growth and interlinkage. The favorable grain boundary characteristics result from mechanical dynamic recovery, achieved by the competitive effects of solid-solution strengthening and stacking fault energy. Thus, the present study provides novel insights into enhancing HE resistance in FCC-structured alloys., Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public., Team Marcel Sluiter

Hydrides based on magnesium and intermetallic compounds provide a viable solution to the challenge of energy storage from renewable sources, thanks to their ability to absorb and desorb hydrogen in a reversible way with a proper tuning of pressure and temperature conditions. Therefore, they are expected to play an important role in the clean energy transition and in the deployment of hydrogen as an efficient energy vector. This review, by experts of Task 40 'Energy Storage and Conversion based on Hydrogen' of the Hydrogen Technology Collaboration Programme of the International Energy Agency, reports on the latest activities of the working group 'Magnesium- and Intermetallic alloys-based Hydrides for Energy Storage'. The following topics are covered by the review: multiscale modelling of hydrides and hydrogen sorption mechanisms; synthesis and processing techniques; catalysts for hydrogen sorption in Mg; Mg-based nanostructures and new compounds; hydrides based on intermetallic TiFe alloys, high entropy alloys, Laves phases, and Pd-containing alloys. Finally, an outlook is presented on current worldwide investments and future research directions for hydrogen-based energy storage.

Nerve growth factor (NGF) is the best-characterized neurotrophin and is primarily recognized for its key role in the embryonic development of the nervous system and neuronal cell survival/differentiation. Recently, unexpected actions of NGF in bone regeneration have emerged as NGF is able to enhance the osteogenic differentiation of mesenchymal stem cells. However, little is known regarding how NGF signaling regulates osteogenic differentiation through epigenetic mechanisms. In this study, using human dental mesenchymal stem cells (DMSCs), we demonstrated that NGF mediates osteogenic differentiation through p75NTR, a low-affinity NGF receptor. P75NTR-mediated NGF signaling activates the JNK cascade and the expression of KDM4B, an activating histone demethylase, by removing repressive H3K9me3 epigenetic marks. Mechanistically, NGF-activated c-Jun binds to the KDM4B promoter region and directly upregulates KDM4B expression. Subsequently, KDM4B directly and epigenetically activates DLX5, a master osteogenic gene, by demethylating H3K9me3 marks. Furthermore, we revealed that KDM4B and c-Jun from the JNK signaling pathway work in concert to regulate NGF-mediated osteogenic differentiation through simultaneous recruitment to the promoter region of DLX5. We identified KDM4B as a key epigenetic regulator during the NGF-mediated osteogenesis both in vitro and in vivo using the calvarial defect regeneration mouse model. In conclusion, our study thoroughly elucidated the molecular and epigenetic mechanisms during NGF-mediated osteogenesis.

Background Cancer risk has been associated with certain gene variations in microRNA (miRNA), but conflicting evidence warrants re-assessing of significant results in meta-analyses. We summarized published meta-analyses that assess the associations between miRNA polymorphism and cancers to show the validity of the findings. Method We searched PubMed and investigated the results of meta-analyses published through November 2018. We re-assessed the results based on false-positive report probability (FPRP) to test the noteworthiness of the associations. Results Sixty-eight miRNA polymorphisms in 45 meta-analyses associated with cancer were included. Four (7.4%) and sixteen (25.0%) single nucleotide polymorphisms (SNPs) were noteworthy (FPRP < 0.2) at a prior probability of 0.001 for interesting candidate genes and a statistical power to detect an odds ratio (OR) of 1.1 and 1.5, respectively. The four miRNA SNPs noteworthy at an OR of 1.1 were as follows: miR-146a/rs2910164 Cvs.G; miR-27a/rs895819 Cvs.T; miR-423/rs6505162 Cvs.A; and miR-605/rs2043556 Cvs.T. The 16 SNPs noteworthy at an OR of 1.5 include the four genotype comparisons at an OR of 1.1, and the additional 12 genotype comparisons were as follows: miR-196a2/rs11614913 Tvs.C; miR-27a/rs895819 GGvs.AA + AG; miR-196a2/rs11614913 C vs.T; miR-146a/rs2910164 Gvs.C; miR-196a2/rs11614913 Tvs.C; miR-146a/rs2910164 Cvs.G; miR-499/rs3746444 homozygous model; miR-146a/rs2910164 CCvs.GG + GC; miR-499/rs3746444 TCvs.TT; miR-499/rs3746444 GAvs.AA; miR-146a/rs2910164 CCvs.GG; and miR-499/rs3746444 Gvs.A. No association was noteworthy at a prior probability of 0.000001. Conclusion Out of 68 published associations of miRNA polymorphisms with cancer, sixteen have shown noteworthiness in our re-assessing meta-analysis. Our findings summarize the results of meta-analyses on the association of cancer with SNPs and underline the importance of interpreting results with caution.

Suh JW, Ju Y, Lee CK, et al. Infect Drug Resist. 2019;12:161–171. On page 161, in “Abstract: Results” section, the text “Fifty-two (77.6%) isolates showed multidrug resistance, defined as resistance to ≥3 different antibiotic families” should read “Fifty-four (80.6%) isolates showed multidrug resistance, defined as resistance to ≥ 3 different antibiotic families.”   Page 164, in “Antimicrobial susceptibility” section, first sentence, “All strains were susceptible to erythromycin, vancomycin, linezolid and daptomycin (Table 3).” should read “All strains were susceptible to vancomycin, linezolid, and daptomycin (Table 3).” Page 165, in “Antimicrobial susceptibility” section, second sentence, “Therefore, the 67 strains may be considered multidrug resistant, defined as resistance to ≥3 classes of antibiotics” should read “Therefore, the 54 strains may be considered multidrug-resistant, defined as resistance to ≥ 3 classes of antibiotics.”   Read the original article here

Jin Woong Suh,1 Yongguk Ju,2 Chang Kyu Lee,3 Jang Wook Sohn,1,2 Min Ja Kim,1,2 Young Kyung Yoon1,2 1Division of Infectious Diseases, Department of Internal Medicine, Korea University College of Medicine, Seoul, Republic of Korea; 2Institute of Emerging Infectious Diseases, Korea University College of Medicine, Seoul, Republic of Korea; 3Department of Laboratory Medicine, Korea University College of Medicine, Seoul, Republic of Korea Purpose: This study investigated the clinical epidemiology, antimicrobial susceptibility, and molecular epidemiology of Corynebacterium striatum isolates.Patients and methods: An observational study was conducted at a university hospital in the Republic of Korea from August to December 2016. All subjects were patients who tested positive for C. striatum clinically. Clinical data were analyzed to evaluate the microbiological and genotypic characteristics of C. striatum strains.Results: Sixty-seven C. striatum isolates recovered from non-duplicated patients were characterized. Patients were classified into three groups according to the infection type: nosocomial infection (71.6%), health care-associated infection (8.7%), and community-acquired infection (18.8%). The most common clinical specimens were urine (35.8%) and skin abscesses (32.8%). Fifty-two (77.6%) isolates showed multidrug resistance, defined as resistance to ≥3 different antibiotic families. All strains were susceptible to vancomycin and linezolid. Resistance to other antibiotics varied: penicillin (n=65; 97.0%), ampicillin (n=63; 94.0%), cefotaxime (n=64; 95.5%), and levofloxacin (n=61; 91.0%). Phylogenetic analysis identified all 16 S rRNA gene sequences of the 67 isolates as those of C. striatum, where 98%–99% were homologous to C. striatum ATCC 6940. In multilocus sequence typing for internal transcribed spacer region, gyrA, and rpoB sequencing, the most predominant sequence types (STs) were ST2, ST3, ST6, and ST5.Conclusion: C. striatum isolates may caus

The fracture toughness of three new compositional variants of the Zr-Ti-Be-LTM (Late Transition Metal) family of bulk metallic glasses (BMG's) are studied in the as-cast and annealed condition. Quaternary Zr-Ti-Cu-Be alloys consistently had linear elastic fracture toughness values greater than 80 MPa∙m1/2, while Vitreloy 1, a Zr-Ti-Cu-Ni-Be alloy, had an average fracture toughness of 48.5 MPa∙m1/2 with a large amount of scatter. The addition of iron to Vitreloy 1 reduced the fracture toughness to 25 MPa∙m1/2. The Zr-Ti-Cu-Be alloy, having fracture toughness KQ = 85 MPa∙m1/2 as cast, was annealed at various time/temperature combinations. When the alloy was annealed 50C below Tg, the fracture toughness dropped to 6 MPa∙m1/2, while DSC and X-ray showed the alloy to still be amorphous. Fracture surfaces were analyzed using scanning electron microscopy. The tougher samples have shown evidence of highly jagged patterns at the beginning stage of crack propagation, and the length scale and roughness of this jagged pattern correlate well with the measured fracture toughness values. These jagged patterns, the main source of energy dissipation in the sample, are attributed to the formation of shear bands inside the sample. This observation provides a strong evidence of significant “plastic zone” screening at the crack tip. Unlike the unstable fracture behavior of monolithic BMG's, ductile phase containing in-situ BMG composite shows stable crack growth behavior. Application of ductile BMG as a matrix for an in-situ composite with controlled microstructural characteristic length scales maximizes the toughening effect. In order to characterize this highly toughened BMG composite, the elastic-plastic fracture mechanics concept is introduced and the J-parameter is evaluated. A novel thermoplastic bonding concept is demonstrated based on the unique rheological behavior and pattern-replicat

Suk Hyun Choi,1,* Jue Yeon Lee,2,* Jin Sook Suh,1 Yoon Shin Park,3 Chong Pyoung Chung,2 Yoon Jeong Park1 1Department of Dental Regenerative Biotechnology, Dental Research Institute, 2Central Research Institute, Nano Intelligent Biomedical Engineering Corporation (NIBEC), School of Dentistry, Seoul National University, Seoul, 3Department in Microbiology, School of Biological Sciences, College of Natural Sciences, Chungbuk National University, Cheongju, South Korea *These authors contributed equally to this work Abstract: Angiogenesis plays a critical role in the growth and metastasis of cancer, and growth factors released from cancer promote blood-vessel formation in the tumor microenvironment. The angiogenesis is accelerated via interactions of growth factors with the high-affinity receptors on cancer cells. In particular, heparan sulfate proteoglycans (HSPGs) on the surface of cancer cells have been shown to be important in many aspects of determining a tumor’s phenotype and development. Specifically, the regulation of the interactions between HSPGs and growth factors results in changes in tumor progression. A peptide with heparin-binding (HBP) activity has been developed and synthesized to inhibit tumor growth via the prevention of angiogenesis. We hypothesized that HBP could inhibit the interaction of growth factors and HSPGs on the surface of cancer cells, decrease paracrine signaling in endothelial cells (ECs), and finally decrease angiogenesis in the tumor microenvironment. In this study, we found that HBP had antiangiogenic effects in vitro and in vivo. The conditioned media obtained from a breast cancer cell line treated with HBP were used to culture human umbilical vein ECs (HUVECs) to evaluate the antiangiogenic effect of HBP on ECs. HBP effectively inhibited the migration, invasion, and tube formation of HUVECs in vitro. In addition, the expressions of angiogenesis-mediating factors, including ERK, FAK, and Akt, were considerably decreased. HBP

Jue Yeon Lee,1,* Jin Sook Suh,2,* Jung Min Kim,1 Jeong Hwa Kim,1 Hyun Jung Park,1 Yoon Jeong Park,1,2 Chong Pyoung Chung1 1Central Research Institute, Nano Intelligent Biomedical Engineering Corporation (NIBEC), Chungcheongbuk-do, Republic of Korea; 2Dental Regenerative Biotechnology, Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Republic of Korea *These authors contributed equally to this work Abstract: Human beta-defensins (hBDs) are crucial factors of intrinsic immunity that function in the immunologic response to a variety of invading enveloped viruses, bacteria, and fungi. hBDs can cause membrane depolarization and cell lysis due to their highly cationic nature. These molecules participate in antimicrobial defenses and the control of adaptive and innate immunity in every mammalian species and are produced by various cell types. The C-terminal 15-mer peptide within hBD3, designated as hBD3-3, was selected for study due to its cell- and skin-penetrating activity, which can induce anti-inflammatory activity in lipopolysaccharide-treated RAW 264.7 macrophages. hBD3-3 penetrated both the outer membrane of the cells and mouse skin within a short treatment period. Two other peptide fragments showed poorer penetration activity compared to hBD3-3. hBD3-3 inhibited the lipopolysaccharide-induced production of inducible nitric oxide synthase, nitric oxide, and secretory cytokines, such as interleukin-6 and tumor necrosis factor in a concentration-dependent manner. Moreover, hBD3-3 reduced the interstitial infiltration of polymorphonuclear leukocytes in a lung inflammation model. Further investigation also revealed that hBD3-3 downregulated nuclear factor kappa B-dependent inflammation by directly suppressing the degradation of phosphorylated-IκBα and by downregulating active nuclear factor kappa B p65. Our findings indicate that hBD3-3 may be conjugated with drugs of interest to ensure their proper transloca

Aastha Kukreja,1 Eun-Kyung Lim,2–4 Byunghoon Kang,1 Yuna Choi,2 Taeksu Lee,1 Jin-Suck Suh,2,3 Yong-Min Huh,2,3 Seungjoo Haam1,31Department of Chemical and Biomolecular Engineering, College of Engineering, 2Department of Radiology, College of Medicine, Yonsei University, Seoul, Republic of Korea; 3YUHS-KRIBB Medical Convergence Research Institute, Seoul, Republic of Korea; 4BioNanotechnology Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of KoreaAbstract: In this study, dextran-encrusted magnetic nanoclusters (DMNCs) were synthesized using a one-pot solution phase method for detection of atherosclerosis by magnetic resonance imaging. Pyrenyl dextran was used as a surfactant because of its electron-stabilizing effect and its amphiphilic nature, rendering the DMNCs stable and water-dispersible. The DMNCs were 65.6±4.3 nm, had a narrow size distribution, and were superparamagnetic with a high magnetization value of 60.1 emu/g. Further, they showed biocompatibility and high cellular uptake efficiency, as indicated by a strong interaction between dextran and macrophages. In vivo magnetic resonance imaging demonstrated the ability of DMNCs to act as an efficient magnetic resonance imaging contrast agent capable of targeted detection of atherosclerosis. In view of these findings, it is concluded that DMNCs can be used as magnetic resonance imaging contrast agents to detect inflammatory disease.Keywords: magnetic nanocrystal, magnetic resonance imaging, atherosclerosis, macrophages, dextran

Jin Sook Suh,1,* Jue Yeon Lee,2,* Yoon Jung Choi,1 Hyung Keun You,3 Seong-Doo Hong,4 Chong Pyoung Chung,2 Yoon Jeong Park1,2 1Dental Regenerative Biotechnology, Dental Research Institute, School of Dentistry, Seoul National University, Seoul, 2Central Research Institute, Nano Intelligent Biomedical Engineering Corporation (NIBEC), Seoul, 3Department of Periodontology, College of Dentistry, Wonkwang University, Iksan, 4Department of Oral Pathology, School of Dentistry, Seoul National University, Seoul, Republic of Korea *These authors contributed equally to this work Abstract: Protein-transduction technology has been attempted to deliver macromolecular materials, including protein, nucleic acids, and polymeric drugs, for either diagnosis or therapeutic purposes. Herein, fusion protein composed of an arginine-rich cell-penetrating peptide, termed low-molecular-weight protamine (LMWP), and a transcriptional coactivator with a PDZ-binding motif (TAZ) protein was prepared and applied in combination with biomaterials to increase bone-forming capacity. TAZ has been recently identified as a specific osteogenic stimulating transcriptional coactivator in human mesenchymal stem cell (hMSC) differentiation, while simultaneously blocking adipogenic differentiation. However, TAZ by itself cannot penetrate the cells, and thus needs a transfection tool for translocalization. The LMWP-TAZ fusion proteins were efficiently translocalized into the cytosol of hMSCs. The hMSCs treated with cell-penetrating LMWP-TAZ exhibited increased expression of osteoblastic genes and protein, producing significantly higher quantities of mineralized matrix compared to free TAZ. In contrast, adipogenic differentiation of the hMSCs was blocked by treatment of LMWP-TAZ fusion protein, as reflected by reduced marker-protein expression, adipocyte fatty acid-binding protein 2, and peroxisome proliferator-activated receptor-γ messenger ribonucleic acid levels. LMWP-TAZ was applied in alginate gel f

In this study, a cell-penetrating peptide, the transactivating transcriptional factor (TAT) domain from HIV, was linked to a chitosan/doxorubicin (chitosan/DOX) conjugate to form a chitosan/DOX/TAT hybrid. The synthesized chitosan/DOX/TAT conjugate showed a different intracellular distribution pattern from a conjugate without TAT. Unlike both free DOX and the conjugate without TAT, the chitosan/DOX/TAT conjugate was capable of efficient cell entry. The chitosan/DOX/TAT conjugate was found to be highly cytotoxic, with an IC 50 value of approximately 480 nM, 2 times less than that of chitosan/DOX (980 nM). The chitosan/DOX/TAT provided decreases in tumor volume of 77.4 and 57.5% compared to free DOX and chitosan/DOX, respectively, in tumor-bearing mice. Therefore, this study suggests that TAT-mediated chitosan/DOX conjugate delivery is effective in slowing tumor growth.

New processing possibilities are explored for a semi-solidly-processed bulk metallic glass matrix composite based on the ZrTiNbCuBe system. Thermoplastic processing in the supercooled liquid region, extensive room temperature cold-rolling, and tensile ductility with work-hardening are all achieved. This research demonstrates that bulk metallic glass matrix composites have potential that far exceeds high tensile ductility and ultra-high toughness.

A novel thermoplastic bonding concept is demonstrated based on the unique rheological behavior and pattern-replicating ability of bulk metallic glass (BMG)-forming liquids. In this approach, the BMG is heated above Tg to the “supercooled liquid” region while a small normal force is applied to the joint. This results in liquid reflow, wetting and a strong bond. Complete wetting between copper substrates and a layer of platinum-based BMG leads to an atomistically intimate void-free interface.