Heavy metal pollution has always been a serious environmental problem widely concerned by researchers all around the world. On the other side, the accumulation of biowastes has also occupied a large ...amount of space and caused a series of environment pollution. In this study, the waste oyster shell, was applied as a type of biogenic carbonate material for Pb(II) removal from the aquatic environment, and further as a remediation agent for metal stabilization in the contaminated river sediment. After simple pretreatment, the oyster shell powder (OSP) was characterized, and the results showed that the prepared OSP is mainly composed of calcite with particle size of micron-level. The OSP exhibited excellent Pb(II) adsorption performance, with the adsorption capacity as 639.9 mg/g through adsorption isotherm study. Furthermore, the OSP was applied to remediate the collected river sediment artificially contaminated by Pb(II). It was found that the proportion of residual Pb fraction (F4) was greatly increased from 39.6% of the original sediment to 76.7% in the 14-day incubated sediment with OSP. The Pb(II) concentration after leaching procedure was decreased from 810.7 to 108.6 μg/L even after 5-day incubation. Therefore, this study shows the potential of using waste oyster shell as adsorbent and amendment agent for effective metal immobilization in both aquatic and sediment systems.
Graphic abstract
Objectives
The present study aimed to investigate whether exosomes derived from miR‐375‐overexpressing human adipose mesenchymal stem cells (hASCs) could enhance bone regeneration.
Materials and ...Methods
Exosomes enriched with miR‐375 (Exo miR‐375) were generated from hASCs stably overexpressing miR‐375 after lentiviral transfection and identified with transmission electron microscopy, nanosight and western blotting. The construction efficiency of Exo (miR‐375) was evaluated with qRT‐PCR and incubated with human bone marrow mesenchymal stem cells (hBMSCs) to optimize the effective dosage. Then, the osteogenic capability of Exo (miR‐375) was investigated with ALP and ARS assays. Furthermore, dual‐luciferase reporter assay and western blotting were conducted to reveal the underlying mechanism of miR‐375 in osteogenic regulation. Finally, Exo (miR‐375) were embedded with hydrogel and applied to a rat model of calvarial defect, and μ‐CT analysis and histological examination were conducted to evaluate the therapeutic effects of Exo (miR‐375) in bone regeneration.
Results
miR‐375 could be enriched in exosomes by overexpressing in the parent cells. Administration of Exo (miR‐375) at 50 μg/mL improved the osteogenic differentiation of hBMSCs. With miR‐375 absorbed by hBMSCs, insulin‐like growth factor binding protein 3 (IGFBP3) was inhibited by binding to its 3′UTR, and recombinant IGFBP3 protein reduced the osteogenic effects triggered by Exo (miR‐375). After incorporated with hydrogel, Exo (miR‐375) displayed a slow and controlled release, and further in vivo analysis demonstrated that Exo (miR‐375) enhanced the bone regenerative capacity in a rat model of calvarial defect.
Conclusions
Taken together, our study demonstrated that exosomes derived from miR‐375‐overexpressing hASCs promoted bone regeneration.
Compressed sensing (CS) has exhibited great potential for accelerating magnetic resonance imaging (MRI). In CS-MRI, we want to reconstruct a high-quality image from very few samples in a short time. ...In this paper, we propose a fast algorithm, called projected iterative soft-thresholding algorithm (pISTA), and its acceleration pFISTA for CS-MRI image reconstruction. The proposed algorithms exploit sparsity of the magnetic resonance (MR) images under the redundant representation of tight frames. We prove that pISTA and pFISTA converge to a minimizer of a convex function with a balanced tight frame sparsity formulation. The pFISTA introduces only one adjustable parameter, the step size, and we provide an explicit rule to set this parameter. Numerical experiment results demonstrate that pFISTA leads to faster convergence speeds than the state-of-art counterpart does, while achieving comparable reconstruction errors. Moreover, reconstruction errors incurred by pFISTA appear insensitive to the step size.
Osteogenic differentiation and bone formation is suppressed under condition of inflammation induced by proinflammation cytokines. A number of studies indicate miRNAs play a significant role in tumor ...necrosis factor‐α‐induced inhibition of bone formation, but whether long non‐coding RNAs are also involved in this process remains unknown. In this study, we evaluated the role of MIR31HG in osteogenesis of human adipose‐derived stem cells (hASCs) in vitro and in vivo. The results suggested that knockdown of MIR31HG not only significantly promoted osteogenic differentiation, but also dramatically overcame the inflammation‐induced inhibition of osteogenesis in hASCs. Mechanistically, we found MIR31HG regulated bone formation and inflammation via interacting with NF‐κB. The p65 subunit bound to the MIR31HG promoter and promoted MIR31HG expression. In turn, MIR31HG directly interacted with IκBα and participated in NF‐κB activation, which builds a regulatory circuitry with NF‐κB. Targeting this MIR31HG–NF‐κB regulatory loop may be helpful to improve the osteogenic capacity of hASCs under inflammatory microenvironment in bone tissue engineering. Stem Cells 2016;34:2707–2720
Schematic of the regulatory circuitry of MIR31HG and NF‐κB. Under TNF‐α and IL‐17 stimulation, MIR31HG directly binds to IκBα and contributes to IκBα phosphorylation and NF‐κB activation. The nuclear translocation of NF‐κB in turn binds to MIR31HG promoter, upregulates its expression, and promotes its export to the cytoplasm where it exerts its function.
Abstract Nanostructured materials can direct stem cell lineage commitment solely by their various, but controllable, geometric cues, which would be very important for their future application in bone ...tissue engineering and bone regeneration. However, the mechanisms by which nano-geometric cues dictate the osteogenic differentiation of stem cells remain unclear. Epigenetics is central to cellular differentiation, a process that regulates heritable and long-lasting alterations in gene expression without changing the DNA sequence. Here, we explored the varied osteogenic behaviors of human adipose-derived stem cells (hASCs) on titanium dioxide (TiO2 ) nanotube arrays of different diameters. Both in vitro and in vivo studies demonstrated that the nanoscale geometry influenced cellular differentiation and TiO2 nanotubes with a diameter of 70 nm was the optimal dimension for the osteogenic differentiation of hASCs. Moreover, we observed that TiO2 nanotubes promoted the osteogenic differentiation of hASCs by upregulating methylation level of histone H3 at lysine 4 (H3K4) in the promoter regions of osteogenic genes Runx2 and osteocalcin, by inhibiting demethylase retinoblastoma binding protein 2 (RBP2). These results revealed, for the first time, the epigenetic mechanism by which nanotopography directs stem cell fate.
The oral and maxillofacial regions have complex anatomical structures and different tissue types, which have vital health and aesthetic functions. Biodegradable metals (BMs) is a promising bioactive ...materials to treat oral and maxillofacial diseases. This review summarizes the research status and future research directions of BMs for oral and maxillofacial applications. Mg-based BMs and Zn-based BMs for bone fracture fixation systems, and guided bone regeneration (GBR) membranes, are discussed in detail. Zn-based BMs with a moderate degradation rate and superior mechanical properties for GBR membranes show great potential for clinical translation. Fe-based BMs have a relatively low degradation rate and insoluble degradation products, which greatly limit their application and clinical translation. Furthermore, we proposed potential future research directions for BMs in the oral and maxillofacial regions, including 3D printed BM bone scaffolds, surface modification for BMs GBR membranes, and BMs containing hydrogels for cartilage regeneration, soft tissue regeneration, and nerve regeneration. Taken together, the progress made in the development of BMs in oral and maxillofacial regions has laid a foundation for further clinical translation.
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•The research status of biodegradable metals for oral and maxillofacial applications is systematically reviewed.•The future research directions of biodegradable metals or oral and maxillofacial applications are prospected. .•Zn-based GBR membranes show great potential for clinical translation.
The application of virtual reality has become increasingly extensive as this technology has developed. In dental education, virtual reality is mainly used to assist or replace traditional methods of ...teaching clinical skills in preclinical training for several subjects, such as endodontics, prosthodontics, periodontics, implantology, and dental surgery. The application of dental simulators in teaching can make up for the deficiency of traditional teaching methods and reduce the teaching burden, improving convenience for both teachers and students. However, because of the technology limitations of virtual reality and force feedback, dental simulators still have many hardware and software disadvantages that have prevented them from being an alternative to traditional dental simulators as a primary skill training method. In the future, when combined with big data, cloud computing, 5G, and deep learning technology, dental simulators will be able to give students individualized learning assistance, and their functions will be more diverse and suitable for preclinical training. The purpose of this review is to provide an overview of current dental simulators on related technologies, advantages and disadvantages, methods of evaluating effectiveness, and future directions for development.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The origin of life and native tissue development are dependent on the heterogeneity of pluripotent stem cells. Bone marrow mesenchymal stem cells (BMMSCs) are located in a complicated niche with ...variable matrix stiffnesses, resulting in divergent stem cell fates. However, how stiffness drives stem cell fate remains unknown. For this study, we performed whole-gene transcriptomics and precise untargeted metabolomics sequencing to elucidate the complex interaction network of stem cell transcriptional and metabolic signals in extracellular matrices (ECMs) with different stiffnesses, and we propose a potential mechanism involved in stem cell fate decision. In a stiff (39~45 kPa) ECM, biosynthesis of aminoacyl-tRNA was up-regulated, and increased osteogenesis was also observed. In a soft (7~10 kPa) ECM, biosynthesis of unsaturated fatty acids and deposition of glycosaminoglycans were increased, accompanied by enhanced adipogenic/chondrogenic differentiation of BMMSCs. In addition, a panel of genes responding to the stiffness of the ECM were validated in vitro, mapping out the key signaling network that regulates stem cells' fate decisions. This finding of "stiffness-dependent manipulation of stem cell fate" provides a novel molecular biological basis for development of potential therapeutic targets within tissue engineering, from both a cellular metabolic and a biomechanical perspective.
Therapies based on the combination of immune checkpoint inhibitors (ICIs) and thoracic radiotherapy (TRT) are transforming the treatment landscape of esophageal cancer. Nevertheless, the available ...data on adverse events (AEs) mainly stemmed from several prospective clinical trials and retrospective studies, in which, AE data are often handled and reported with less rigor than the primary beneficial outcomes of the study. Thus, we conducted a systematic review to investigate the toxicity spectrum of these novel regimens.
We searched for all prospective clinical trials investigating the role of ICIs combined with TRT published between January 2010 and August 2022. Study articles and conference proceedings involving esophageal cancers and reporting the overall incidence or details of treatment-related AEs (trAEs) were synthesized to determine the toxicity profile of combination treatment. We compared trAEs between cancer type, programmed cell death 1 (PD-1) and programmed cell death ligand 1 (PD-L1) inhibitors, and between sequential and concurrent administration of ICIs and TRT to identify potentially high-risk patients.
We obtained toxicity data from 14 clinical trials involving 863 patients. The pooled overall incidence was 88.97% for any-grade trAEs and 18.48% for high-grade trAEs. The three most frequent non-hematologic any-grade trAEs were reactive cutaneous capillary endothelial proliferation (RCCEP, 63.80%), esophagitis (51.54%), and fatigue (33.63%). Meanwhile, RCCEP (15.69%) was the most common non-hematologic high-grade trAE, followed by nausea (4.91%) and anorexia (3.81%). The occurrence rates of any-grade and high-grade pneumonitis were 10.82% and 0.66%, respectively. In subgroup analysis, the toxicity profiles of PD-1 and PD-L1 inhibitors were mostly similar, except for any-grade pneumonitis (15.20% vs 4.88%, p=0.03) and high-grade leukopenia (6.25% vs 59.09%, p=0.00). In addition, concurrent treatment seemed to have a higher incidence of any-grade trAEs (95.20% vs 70.85%, p=0.03) compared with sequential treatment. ESCC seems to have higher incidence of any-grade hypothyroidism (22.55% vs 8.96%, p=0.049) compared to EAC.
Our study is the first systematic review to provide a toxicity profile of trAEs in esophageal cancer patients who received ICIs combined with TRT. Most AEs of this combination treatment are tolerable, although the incidence of any-grade trAEs was higher in the concurrent group. The difference in any-grade pneumonitis between PD-1 and PD-L1 inhibitor groups needs further validation in a large clinical trial.
The large heat input welding performance of shipbuilding steel could be improved effectively by Mg treated in steelmaking process, but the mechanism of Mg on the nano-scale pinned particles had not ...been figured out yet, and this is also the bottleneck for Mg oxide metallurgy developing. In this research, with Mg-treated shipbuilding steel produced by industrial trials, the systematic experiments and theoretical analysis of thermodynamics and crystallography had been done. The results showed that, with increased welding energy, as the core pinned particles, the quantity of particles between 40 nm and 120 nm was stable when the welding energy was <250 kJ/cm. During welding process, a number of reversible chemical reactions involving Mg and MgO generation or consumption occurred in the heat affect zone for Mg treated shipbuilding steel, and the temperature for more MgO formation just meet the thermodynamic conditions that the solid solution behavior of pinned particles TiN started to accelerate. Due to the extremely low disregistry value between MgO and TiN, the newly generated MgO which was determined by the Mg content in steel was highly likely to precipitate on the original TiN particles, delayed the solid solution of TiN, and generated more stable pinned particles.
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•The pinned particles of Mg treated shipbuilding steel under large heat input welding had been analyzed.•As welding energy increased, the grains of welding HAZ had not coarsened.•Mg could react with Ti2O3 and Al2O3 to form MgO under high temperature.•MgO could precipitate on the surface of TiN particles, inhibited the dissolution of TiN and enhanced the stability of pinned particles.
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